diff --git a/pytz/__init__.py b/pytz/__init__.py
index e2f49fa..65c1d11 100644
--- a/pytz/__init__.py
+++ b/pytz/__init__.py
@@ -74,6 +74,9 @@ else:  # Python 2.x
         """
         return s.encode('ASCII')
 
+_tzinfo_dir = os.getenv('PYTZ_TZDATADIR') or '/usr/share/zoneinfo'
+if _tzinfo_dir.endswith(os.sep):
+    _tzinfo_dir = _tzinfo_dir[:-1]
 
 def open_resource(name):
     """Open a resource from the zoneinfo subdir for reading.
@@ -88,23 +91,8 @@ def open_resource(name):
     for part in name_parts:
         if part == os.path.pardir or os.path.sep in part:
             raise ValueError('Bad path segment: %r' % part)
-    zoneinfo_dir = os.environ.get('PYTZ_TZDATADIR', None)
-    if zoneinfo_dir is not None:
-        filename = os.path.join(zoneinfo_dir, *name_parts)
-    else:
-        filename = os.path.join(os.path.dirname(__file__),
-                                'zoneinfo', *name_parts)
-        if not os.path.exists(filename):
-            # http://bugs.launchpad.net/bugs/383171 - we avoid using this
-            # unless absolutely necessary to help when a broken version of
-            # pkg_resources is installed.
-            try:
-                from pkg_resources import resource_stream
-            except ImportError:
-                resource_stream = None
-
-            if resource_stream is not None:
-                return resource_stream(__name__, 'zoneinfo/' + name)
+    zoneinfo_dir = os.environ.get('PYTZ_TZDATADIR', _tzinfo_dir)
+    filename = os.path.join(zoneinfo_dir, *name_parts)
     return open(filename, 'rb')
 
 
--- a/pytz/__init__.py~	2021-10-04 09:16:08.981477792 -0500
+++ b/pytz/__init__.py	2021-10-04 11:29:19.283758542 -0500
@@ -502,1045 +502,37 @@
 
 if __name__ == '__main__':
     _test()
-all_timezones = \
-['Africa/Abidjan',
- 'Africa/Accra',
- 'Africa/Addis_Ababa',
- 'Africa/Algiers',
- 'Africa/Asmara',
- 'Africa/Asmera',
- 'Africa/Bamako',
- 'Africa/Bangui',
- 'Africa/Banjul',
- 'Africa/Bissau',
- 'Africa/Blantyre',
- 'Africa/Brazzaville',
- 'Africa/Bujumbura',
- 'Africa/Cairo',
- 'Africa/Casablanca',
- 'Africa/Ceuta',
- 'Africa/Conakry',
- 'Africa/Dakar',
- 'Africa/Dar_es_Salaam',
- 'Africa/Djibouti',
- 'Africa/Douala',
- 'Africa/El_Aaiun',
- 'Africa/Freetown',
- 'Africa/Gaborone',
- 'Africa/Harare',
- 'Africa/Johannesburg',
- 'Africa/Juba',
- 'Africa/Kampala',
- 'Africa/Khartoum',
- 'Africa/Kigali',
- 'Africa/Kinshasa',
- 'Africa/Lagos',
- 'Africa/Libreville',
- 'Africa/Lome',
- 'Africa/Luanda',
- 'Africa/Lubumbashi',
- 'Africa/Lusaka',
- 'Africa/Malabo',
- 'Africa/Maputo',
- 'Africa/Maseru',
- 'Africa/Mbabane',
- 'Africa/Mogadishu',
- 'Africa/Monrovia',
- 'Africa/Nairobi',
- 'Africa/Ndjamena',
- 'Africa/Niamey',
- 'Africa/Nouakchott',
- 'Africa/Ouagadougou',
- 'Africa/Porto-Novo',
- 'Africa/Sao_Tome',
- 'Africa/Timbuktu',
- 'Africa/Tripoli',
- 'Africa/Tunis',
- 'Africa/Windhoek',
- 'America/Adak',
- 'America/Anchorage',
- 'America/Anguilla',
- 'America/Antigua',
- 'America/Araguaina',
- 'America/Argentina/Buenos_Aires',
- 'America/Argentina/Catamarca',
- 'America/Argentina/ComodRivadavia',
- 'America/Argentina/Cordoba',
- 'America/Argentina/Jujuy',
- 'America/Argentina/La_Rioja',
- 'America/Argentina/Mendoza',
- 'America/Argentina/Rio_Gallegos',
- 'America/Argentina/Salta',
- 'America/Argentina/San_Juan',
- 'America/Argentina/San_Luis',
- 'America/Argentina/Tucuman',
- 'America/Argentina/Ushuaia',
- 'America/Aruba',
- 'America/Asuncion',
- 'America/Atikokan',
- 'America/Atka',
- 'America/Bahia',
- 'America/Bahia_Banderas',
- 'America/Barbados',
- 'America/Belem',
- 'America/Belize',
- 'America/Blanc-Sablon',
- 'America/Boa_Vista',
- 'America/Bogota',
- 'America/Boise',
- 'America/Buenos_Aires',
- 'America/Cambridge_Bay',
- 'America/Campo_Grande',
- 'America/Cancun',
- 'America/Caracas',
- 'America/Catamarca',
- 'America/Cayenne',
- 'America/Cayman',
- 'America/Chicago',
- 'America/Chihuahua',
- 'America/Coral_Harbour',
- 'America/Cordoba',
- 'America/Costa_Rica',
- 'America/Creston',
- 'America/Cuiaba',
- 'America/Curacao',
- 'America/Danmarkshavn',
- 'America/Dawson',
- 'America/Dawson_Creek',
- 'America/Denver',
- 'America/Detroit',
- 'America/Dominica',
- 'America/Edmonton',
- 'America/Eirunepe',
- 'America/El_Salvador',
- 'America/Ensenada',
- 'America/Fort_Nelson',
- 'America/Fort_Wayne',
- 'America/Fortaleza',
- 'America/Glace_Bay',
- 'America/Godthab',
- 'America/Goose_Bay',
- 'America/Grand_Turk',
- 'America/Grenada',
- 'America/Guadeloupe',
- 'America/Guatemala',
- 'America/Guayaquil',
- 'America/Guyana',
- 'America/Halifax',
- 'America/Havana',
- 'America/Hermosillo',
- 'America/Indiana/Indianapolis',
- 'America/Indiana/Knox',
- 'America/Indiana/Marengo',
- 'America/Indiana/Petersburg',
- 'America/Indiana/Tell_City',
- 'America/Indiana/Vevay',
- 'America/Indiana/Vincennes',
- 'America/Indiana/Winamac',
- 'America/Indianapolis',
- 'America/Inuvik',
- 'America/Iqaluit',
- 'America/Jamaica',
- 'America/Jujuy',
- 'America/Juneau',
- 'America/Kentucky/Louisville',
- 'America/Kentucky/Monticello',
- 'America/Knox_IN',
- 'America/Kralendijk',
- 'America/La_Paz',
- 'America/Lima',
- 'America/Los_Angeles',
- 'America/Louisville',
- 'America/Lower_Princes',
- 'America/Maceio',
- 'America/Managua',
- 'America/Manaus',
- 'America/Marigot',
- 'America/Martinique',
- 'America/Matamoros',
- 'America/Mazatlan',
- 'America/Mendoza',
- 'America/Menominee',
- 'America/Merida',
- 'America/Metlakatla',
- 'America/Mexico_City',
- 'America/Miquelon',
- 'America/Moncton',
- 'America/Monterrey',
- 'America/Montevideo',
- 'America/Montreal',
- 'America/Montserrat',
- 'America/Nassau',
- 'America/New_York',
- 'America/Nipigon',
- 'America/Nome',
- 'America/Noronha',
- 'America/North_Dakota/Beulah',
- 'America/North_Dakota/Center',
- 'America/North_Dakota/New_Salem',
- 'America/Nuuk',
- 'America/Ojinaga',
- 'America/Panama',
- 'America/Pangnirtung',
- 'America/Paramaribo',
- 'America/Phoenix',
- 'America/Port-au-Prince',
- 'America/Port_of_Spain',
- 'America/Porto_Acre',
- 'America/Porto_Velho',
- 'America/Puerto_Rico',
- 'America/Punta_Arenas',
- 'America/Rainy_River',
- 'America/Rankin_Inlet',
- 'America/Recife',
- 'America/Regina',
- 'America/Resolute',
- 'America/Rio_Branco',
- 'America/Rosario',
- 'America/Santa_Isabel',
- 'America/Santarem',
- 'America/Santiago',
- 'America/Santo_Domingo',
- 'America/Sao_Paulo',
- 'America/Scoresbysund',
- 'America/Shiprock',
- 'America/Sitka',
- 'America/St_Barthelemy',
- 'America/St_Johns',
- 'America/St_Kitts',
- 'America/St_Lucia',
- 'America/St_Thomas',
- 'America/St_Vincent',
- 'America/Swift_Current',
- 'America/Tegucigalpa',
- 'America/Thule',
- 'America/Thunder_Bay',
- 'America/Tijuana',
- 'America/Toronto',
- 'America/Tortola',
- 'America/Vancouver',
- 'America/Virgin',
- 'America/Whitehorse',
- 'America/Winnipeg',
- 'America/Yakutat',
- 'America/Yellowknife',
- 'Antarctica/Casey',
- 'Antarctica/Davis',
- 'Antarctica/DumontDUrville',
- 'Antarctica/Macquarie',
- 'Antarctica/Mawson',
- 'Antarctica/McMurdo',
- 'Antarctica/Palmer',
- 'Antarctica/Rothera',
- 'Antarctica/South_Pole',
- 'Antarctica/Syowa',
- 'Antarctica/Troll',
- 'Antarctica/Vostok',
- 'Arctic/Longyearbyen',
- 'Asia/Aden',
- 'Asia/Almaty',
- 'Asia/Amman',
- 'Asia/Anadyr',
- 'Asia/Aqtau',
- 'Asia/Aqtobe',
- 'Asia/Ashgabat',
- 'Asia/Ashkhabad',
- 'Asia/Atyrau',
- 'Asia/Baghdad',
- 'Asia/Bahrain',
- 'Asia/Baku',
- 'Asia/Bangkok',
- 'Asia/Barnaul',
- 'Asia/Beirut',
- 'Asia/Bishkek',
- 'Asia/Brunei',
- 'Asia/Calcutta',
- 'Asia/Chita',
- 'Asia/Choibalsan',
- 'Asia/Chongqing',
- 'Asia/Chungking',
- 'Asia/Colombo',
- 'Asia/Dacca',
- 'Asia/Damascus',
- 'Asia/Dhaka',
- 'Asia/Dili',
- 'Asia/Dubai',
- 'Asia/Dushanbe',
- 'Asia/Famagusta',
- 'Asia/Gaza',
- 'Asia/Harbin',
- 'Asia/Hebron',
- 'Asia/Ho_Chi_Minh',
- 'Asia/Hong_Kong',
- 'Asia/Hovd',
- 'Asia/Irkutsk',
- 'Asia/Istanbul',
- 'Asia/Jakarta',
- 'Asia/Jayapura',
- 'Asia/Jerusalem',
- 'Asia/Kabul',
- 'Asia/Kamchatka',
- 'Asia/Karachi',
- 'Asia/Kashgar',
- 'Asia/Kathmandu',
- 'Asia/Katmandu',
- 'Asia/Khandyga',
- 'Asia/Kolkata',
- 'Asia/Krasnoyarsk',
- 'Asia/Kuala_Lumpur',
- 'Asia/Kuching',
- 'Asia/Kuwait',
- 'Asia/Macao',
- 'Asia/Macau',
- 'Asia/Magadan',
- 'Asia/Makassar',
- 'Asia/Manila',
- 'Asia/Muscat',
- 'Asia/Nicosia',
- 'Asia/Novokuznetsk',
- 'Asia/Novosibirsk',
- 'Asia/Omsk',
- 'Asia/Oral',
- 'Asia/Phnom_Penh',
- 'Asia/Pontianak',
- 'Asia/Pyongyang',
- 'Asia/Qatar',
- 'Asia/Qostanay',
- 'Asia/Qyzylorda',
- 'Asia/Rangoon',
- 'Asia/Riyadh',
- 'Asia/Saigon',
- 'Asia/Sakhalin',
- 'Asia/Samarkand',
- 'Asia/Seoul',
- 'Asia/Shanghai',
- 'Asia/Singapore',
- 'Asia/Srednekolymsk',
- 'Asia/Taipei',
- 'Asia/Tashkent',
- 'Asia/Tbilisi',
- 'Asia/Tehran',
- 'Asia/Tel_Aviv',
- 'Asia/Thimbu',
- 'Asia/Thimphu',
- 'Asia/Tokyo',
- 'Asia/Tomsk',
- 'Asia/Ujung_Pandang',
- 'Asia/Ulaanbaatar',
- 'Asia/Ulan_Bator',
- 'Asia/Urumqi',
- 'Asia/Ust-Nera',
- 'Asia/Vientiane',
- 'Asia/Vladivostok',
- 'Asia/Yakutsk',
- 'Asia/Yangon',
- 'Asia/Yekaterinburg',
- 'Asia/Yerevan',
- 'Atlantic/Azores',
- 'Atlantic/Bermuda',
- 'Atlantic/Canary',
- 'Atlantic/Cape_Verde',
- 'Atlantic/Faeroe',
- 'Atlantic/Faroe',
- 'Atlantic/Jan_Mayen',
- 'Atlantic/Madeira',
- 'Atlantic/Reykjavik',
- 'Atlantic/South_Georgia',
- 'Atlantic/St_Helena',
- 'Atlantic/Stanley',
- 'Australia/ACT',
- 'Australia/Adelaide',
- 'Australia/Brisbane',
- 'Australia/Broken_Hill',
- 'Australia/Canberra',
- 'Australia/Currie',
- 'Australia/Darwin',
- 'Australia/Eucla',
- 'Australia/Hobart',
- 'Australia/LHI',
- 'Australia/Lindeman',
- 'Australia/Lord_Howe',
- 'Australia/Melbourne',
- 'Australia/NSW',
- 'Australia/North',
- 'Australia/Perth',
- 'Australia/Queensland',
- 'Australia/South',
- 'Australia/Sydney',
- 'Australia/Tasmania',
- 'Australia/Victoria',
- 'Australia/West',
- 'Australia/Yancowinna',
- 'Brazil/Acre',
- 'Brazil/DeNoronha',
- 'Brazil/East',
- 'Brazil/West',
- 'CET',
- 'CST6CDT',
- 'Canada/Atlantic',
- 'Canada/Central',
- 'Canada/Eastern',
- 'Canada/Mountain',
- 'Canada/Newfoundland',
- 'Canada/Pacific',
- 'Canada/Saskatchewan',
- 'Canada/Yukon',
- 'Chile/Continental',
- 'Chile/EasterIsland',
- 'Cuba',
- 'EET',
- 'EST',
- 'EST5EDT',
- 'Egypt',
- 'Eire',
- 'Etc/GMT',
- 'Etc/GMT+0',
- 'Etc/GMT+1',
- 'Etc/GMT+10',
- 'Etc/GMT+11',
- 'Etc/GMT+12',
- 'Etc/GMT+2',
- 'Etc/GMT+3',
- 'Etc/GMT+4',
- 'Etc/GMT+5',
- 'Etc/GMT+6',
- 'Etc/GMT+7',
- 'Etc/GMT+8',
- 'Etc/GMT+9',
- 'Etc/GMT-0',
- 'Etc/GMT-1',
- 'Etc/GMT-10',
- 'Etc/GMT-11',
- 'Etc/GMT-12',
- 'Etc/GMT-13',
- 'Etc/GMT-14',
- 'Etc/GMT-2',
- 'Etc/GMT-3',
- 'Etc/GMT-4',
- 'Etc/GMT-5',
- 'Etc/GMT-6',
- 'Etc/GMT-7',
- 'Etc/GMT-8',
- 'Etc/GMT-9',
- 'Etc/GMT0',
- 'Etc/Greenwich',
- 'Etc/UCT',
- 'Etc/UTC',
- 'Etc/Universal',
- 'Etc/Zulu',
- 'Europe/Amsterdam',
- 'Europe/Andorra',
- 'Europe/Astrakhan',
- 'Europe/Athens',
- 'Europe/Belfast',
- 'Europe/Belgrade',
- 'Europe/Berlin',
- 'Europe/Bratislava',
- 'Europe/Brussels',
- 'Europe/Bucharest',
- 'Europe/Budapest',
- 'Europe/Busingen',
- 'Europe/Chisinau',
- 'Europe/Copenhagen',
- 'Europe/Dublin',
- 'Europe/Gibraltar',
- 'Europe/Guernsey',
- 'Europe/Helsinki',
- 'Europe/Isle_of_Man',
- 'Europe/Istanbul',
- 'Europe/Jersey',
- 'Europe/Kaliningrad',
- 'Europe/Kiev',
- 'Europe/Kirov',
- 'Europe/Lisbon',
- 'Europe/Ljubljana',
- 'Europe/London',
- 'Europe/Luxembourg',
- 'Europe/Madrid',
- 'Europe/Malta',
- 'Europe/Mariehamn',
- 'Europe/Minsk',
- 'Europe/Monaco',
- 'Europe/Moscow',
- 'Europe/Nicosia',
- 'Europe/Oslo',
- 'Europe/Paris',
- 'Europe/Podgorica',
- 'Europe/Prague',
- 'Europe/Riga',
- 'Europe/Rome',
- 'Europe/Samara',
- 'Europe/San_Marino',
- 'Europe/Sarajevo',
- 'Europe/Saratov',
- 'Europe/Simferopol',
- 'Europe/Skopje',
- 'Europe/Sofia',
- 'Europe/Stockholm',
- 'Europe/Tallinn',
- 'Europe/Tirane',
- 'Europe/Tiraspol',
- 'Europe/Ulyanovsk',
- 'Europe/Uzhgorod',
- 'Europe/Vaduz',
- 'Europe/Vatican',
- 'Europe/Vienna',
- 'Europe/Vilnius',
- 'Europe/Volgograd',
- 'Europe/Warsaw',
- 'Europe/Zagreb',
- 'Europe/Zaporozhye',
- 'Europe/Zurich',
- 'GB',
- 'GB-Eire',
- 'GMT',
- 'GMT+0',
- 'GMT-0',
- 'GMT0',
- 'Greenwich',
- 'HST',
- 'Hongkong',
- 'Iceland',
- 'Indian/Antananarivo',
- 'Indian/Chagos',
- 'Indian/Christmas',
- 'Indian/Cocos',
- 'Indian/Comoro',
- 'Indian/Kerguelen',
- 'Indian/Mahe',
- 'Indian/Maldives',
- 'Indian/Mauritius',
- 'Indian/Mayotte',
- 'Indian/Reunion',
- 'Iran',
- 'Israel',
- 'Jamaica',
- 'Japan',
- 'Kwajalein',
- 'Libya',
- 'MET',
- 'MST',
- 'MST7MDT',
- 'Mexico/BajaNorte',
- 'Mexico/BajaSur',
- 'Mexico/General',
- 'NZ',
- 'NZ-CHAT',
- 'Navajo',
- 'PRC',
- 'PST8PDT',
- 'Pacific/Apia',
- 'Pacific/Auckland',
- 'Pacific/Bougainville',
- 'Pacific/Chatham',
- 'Pacific/Chuuk',
- 'Pacific/Easter',
- 'Pacific/Efate',
- 'Pacific/Enderbury',
- 'Pacific/Fakaofo',
- 'Pacific/Fiji',
- 'Pacific/Funafuti',
- 'Pacific/Galapagos',
- 'Pacific/Gambier',
- 'Pacific/Guadalcanal',
- 'Pacific/Guam',
- 'Pacific/Honolulu',
- 'Pacific/Johnston',
- 'Pacific/Kanton',
- 'Pacific/Kiritimati',
- 'Pacific/Kosrae',
- 'Pacific/Kwajalein',
- 'Pacific/Majuro',
- 'Pacific/Marquesas',
- 'Pacific/Midway',
- 'Pacific/Nauru',
- 'Pacific/Niue',
- 'Pacific/Norfolk',
- 'Pacific/Noumea',
- 'Pacific/Pago_Pago',
- 'Pacific/Palau',
- 'Pacific/Pitcairn',
- 'Pacific/Pohnpei',
- 'Pacific/Ponape',
- 'Pacific/Port_Moresby',
- 'Pacific/Rarotonga',
- 'Pacific/Saipan',
- 'Pacific/Samoa',
- 'Pacific/Tahiti',
- 'Pacific/Tarawa',
- 'Pacific/Tongatapu',
- 'Pacific/Truk',
- 'Pacific/Wake',
- 'Pacific/Wallis',
- 'Pacific/Yap',
- 'Poland',
- 'Portugal',
- 'ROC',
- 'ROK',
- 'Singapore',
- 'Turkey',
- 'UCT',
- 'US/Alaska',
- 'US/Aleutian',
- 'US/Arizona',
- 'US/Central',
- 'US/East-Indiana',
- 'US/Eastern',
- 'US/Hawaii',
- 'US/Indiana-Starke',
- 'US/Michigan',
- 'US/Mountain',
- 'US/Pacific',
- 'US/Samoa',
- 'UTC',
- 'Universal',
- 'W-SU',
- 'WET',
- 'Zulu']
+all_timezones = []
+for root, dirs, files in os.walk(_tzinfo_dir):
+    for exclude in 'posix', 'right':
+        if exclude in dirs:
+            del dirs[dirs.index(exclude)]
+
+    all_timezones.extend(os.path.join(root, tz_file)[len(_tzinfo_dir)+1:]
+            for tz_file in files
+            if tz_file not in ['leapseconds', 'README', 'Theory']
+            and '.' not in tz_file)
+
 all_timezones = LazyList(
         tz for tz in all_timezones if resource_exists(tz))
         
 all_timezones_set = LazySet(all_timezones)
-common_timezones = \
-['Africa/Abidjan',
- 'Africa/Accra',
- 'Africa/Addis_Ababa',
- 'Africa/Algiers',
- 'Africa/Asmara',
- 'Africa/Bamako',
- 'Africa/Bangui',
- 'Africa/Banjul',
- 'Africa/Bissau',
- 'Africa/Blantyre',
- 'Africa/Brazzaville',
- 'Africa/Bujumbura',
- 'Africa/Cairo',
- 'Africa/Casablanca',
- 'Africa/Ceuta',
- 'Africa/Conakry',
- 'Africa/Dakar',
- 'Africa/Dar_es_Salaam',
- 'Africa/Djibouti',
- 'Africa/Douala',
- 'Africa/El_Aaiun',
- 'Africa/Freetown',
- 'Africa/Gaborone',
- 'Africa/Harare',
- 'Africa/Johannesburg',
- 'Africa/Juba',
- 'Africa/Kampala',
- 'Africa/Khartoum',
- 'Africa/Kigali',
- 'Africa/Kinshasa',
- 'Africa/Lagos',
- 'Africa/Libreville',
- 'Africa/Lome',
- 'Africa/Luanda',
- 'Africa/Lubumbashi',
- 'Africa/Lusaka',
- 'Africa/Malabo',
- 'Africa/Maputo',
- 'Africa/Maseru',
- 'Africa/Mbabane',
- 'Africa/Mogadishu',
- 'Africa/Monrovia',
- 'Africa/Nairobi',
- 'Africa/Ndjamena',
- 'Africa/Niamey',
- 'Africa/Nouakchott',
- 'Africa/Ouagadougou',
- 'Africa/Porto-Novo',
- 'Africa/Sao_Tome',
- 'Africa/Tripoli',
- 'Africa/Tunis',
- 'Africa/Windhoek',
- 'America/Adak',
- 'America/Anchorage',
- 'America/Anguilla',
- 'America/Antigua',
- 'America/Araguaina',
- 'America/Argentina/Buenos_Aires',
- 'America/Argentina/Catamarca',
- 'America/Argentina/Cordoba',
- 'America/Argentina/Jujuy',
- 'America/Argentina/La_Rioja',
- 'America/Argentina/Mendoza',
- 'America/Argentina/Rio_Gallegos',
- 'America/Argentina/Salta',
- 'America/Argentina/San_Juan',
- 'America/Argentina/San_Luis',
- 'America/Argentina/Tucuman',
- 'America/Argentina/Ushuaia',
- 'America/Aruba',
- 'America/Asuncion',
- 'America/Atikokan',
- 'America/Bahia',
- 'America/Bahia_Banderas',
- 'America/Barbados',
- 'America/Belem',
- 'America/Belize',
- 'America/Blanc-Sablon',
- 'America/Boa_Vista',
- 'America/Bogota',
- 'America/Boise',
- 'America/Cambridge_Bay',
- 'America/Campo_Grande',
- 'America/Cancun',
- 'America/Caracas',
- 'America/Cayenne',
- 'America/Cayman',
- 'America/Chicago',
- 'America/Chihuahua',
- 'America/Costa_Rica',
- 'America/Creston',
- 'America/Cuiaba',
- 'America/Curacao',
- 'America/Danmarkshavn',
- 'America/Dawson',
- 'America/Dawson_Creek',
- 'America/Denver',
- 'America/Detroit',
- 'America/Dominica',
- 'America/Edmonton',
- 'America/Eirunepe',
- 'America/El_Salvador',
- 'America/Fort_Nelson',
- 'America/Fortaleza',
- 'America/Glace_Bay',
- 'America/Goose_Bay',
- 'America/Grand_Turk',
- 'America/Grenada',
- 'America/Guadeloupe',
- 'America/Guatemala',
- 'America/Guayaquil',
- 'America/Guyana',
- 'America/Halifax',
- 'America/Havana',
- 'America/Hermosillo',
- 'America/Indiana/Indianapolis',
- 'America/Indiana/Knox',
- 'America/Indiana/Marengo',
- 'America/Indiana/Petersburg',
- 'America/Indiana/Tell_City',
- 'America/Indiana/Vevay',
- 'America/Indiana/Vincennes',
- 'America/Indiana/Winamac',
- 'America/Inuvik',
- 'America/Iqaluit',
- 'America/Jamaica',
- 'America/Juneau',
- 'America/Kentucky/Louisville',
- 'America/Kentucky/Monticello',
- 'America/Kralendijk',
- 'America/La_Paz',
- 'America/Lima',
- 'America/Los_Angeles',
- 'America/Lower_Princes',
- 'America/Maceio',
- 'America/Managua',
- 'America/Manaus',
- 'America/Marigot',
- 'America/Martinique',
- 'America/Matamoros',
- 'America/Mazatlan',
- 'America/Menominee',
- 'America/Merida',
- 'America/Metlakatla',
- 'America/Mexico_City',
- 'America/Miquelon',
- 'America/Moncton',
- 'America/Monterrey',
- 'America/Montevideo',
- 'America/Montserrat',
- 'America/Nassau',
- 'America/New_York',
- 'America/Nipigon',
- 'America/Nome',
- 'America/Noronha',
- 'America/North_Dakota/Beulah',
- 'America/North_Dakota/Center',
- 'America/North_Dakota/New_Salem',
- 'America/Nuuk',
- 'America/Ojinaga',
- 'America/Panama',
- 'America/Pangnirtung',
- 'America/Paramaribo',
- 'America/Phoenix',
- 'America/Port-au-Prince',
- 'America/Port_of_Spain',
- 'America/Porto_Velho',
- 'America/Puerto_Rico',
- 'America/Punta_Arenas',
- 'America/Rainy_River',
- 'America/Rankin_Inlet',
- 'America/Recife',
- 'America/Regina',
- 'America/Resolute',
- 'America/Rio_Branco',
- 'America/Santarem',
- 'America/Santiago',
- 'America/Santo_Domingo',
- 'America/Sao_Paulo',
- 'America/Scoresbysund',
- 'America/Sitka',
- 'America/St_Barthelemy',
- 'America/St_Johns',
- 'America/St_Kitts',
- 'America/St_Lucia',
- 'America/St_Thomas',
- 'America/St_Vincent',
- 'America/Swift_Current',
- 'America/Tegucigalpa',
- 'America/Thule',
- 'America/Thunder_Bay',
- 'America/Tijuana',
- 'America/Toronto',
- 'America/Tortola',
- 'America/Vancouver',
- 'America/Whitehorse',
- 'America/Winnipeg',
- 'America/Yakutat',
- 'America/Yellowknife',
- 'Antarctica/Casey',
- 'Antarctica/Davis',
- 'Antarctica/DumontDUrville',
- 'Antarctica/Macquarie',
- 'Antarctica/Mawson',
- 'Antarctica/McMurdo',
- 'Antarctica/Palmer',
- 'Antarctica/Rothera',
- 'Antarctica/Syowa',
- 'Antarctica/Troll',
- 'Antarctica/Vostok',
- 'Arctic/Longyearbyen',
- 'Asia/Aden',
- 'Asia/Almaty',
- 'Asia/Amman',
- 'Asia/Anadyr',
- 'Asia/Aqtau',
- 'Asia/Aqtobe',
- 'Asia/Ashgabat',
- 'Asia/Atyrau',
- 'Asia/Baghdad',
- 'Asia/Bahrain',
- 'Asia/Baku',
- 'Asia/Bangkok',
- 'Asia/Barnaul',
- 'Asia/Beirut',
- 'Asia/Bishkek',
- 'Asia/Brunei',
- 'Asia/Chita',
- 'Asia/Choibalsan',
- 'Asia/Colombo',
- 'Asia/Damascus',
- 'Asia/Dhaka',
- 'Asia/Dili',
- 'Asia/Dubai',
- 'Asia/Dushanbe',
- 'Asia/Famagusta',
- 'Asia/Gaza',
- 'Asia/Hebron',
- 'Asia/Ho_Chi_Minh',
- 'Asia/Hong_Kong',
- 'Asia/Hovd',
- 'Asia/Irkutsk',
- 'Asia/Jakarta',
- 'Asia/Jayapura',
- 'Asia/Jerusalem',
- 'Asia/Kabul',
- 'Asia/Kamchatka',
- 'Asia/Karachi',
- 'Asia/Kathmandu',
- 'Asia/Khandyga',
- 'Asia/Kolkata',
- 'Asia/Krasnoyarsk',
- 'Asia/Kuala_Lumpur',
- 'Asia/Kuching',
- 'Asia/Kuwait',
- 'Asia/Macau',
- 'Asia/Magadan',
- 'Asia/Makassar',
- 'Asia/Manila',
- 'Asia/Muscat',
- 'Asia/Nicosia',
- 'Asia/Novokuznetsk',
- 'Asia/Novosibirsk',
- 'Asia/Omsk',
- 'Asia/Oral',
- 'Asia/Phnom_Penh',
- 'Asia/Pontianak',
- 'Asia/Pyongyang',
- 'Asia/Qatar',
- 'Asia/Qostanay',
- 'Asia/Qyzylorda',
- 'Asia/Riyadh',
- 'Asia/Sakhalin',
- 'Asia/Samarkand',
- 'Asia/Seoul',
- 'Asia/Shanghai',
- 'Asia/Singapore',
- 'Asia/Srednekolymsk',
- 'Asia/Taipei',
- 'Asia/Tashkent',
- 'Asia/Tbilisi',
- 'Asia/Tehran',
- 'Asia/Thimphu',
- 'Asia/Tokyo',
- 'Asia/Tomsk',
- 'Asia/Ulaanbaatar',
- 'Asia/Urumqi',
- 'Asia/Ust-Nera',
- 'Asia/Vientiane',
- 'Asia/Vladivostok',
- 'Asia/Yakutsk',
- 'Asia/Yangon',
- 'Asia/Yekaterinburg',
- 'Asia/Yerevan',
- 'Atlantic/Azores',
- 'Atlantic/Bermuda',
- 'Atlantic/Canary',
- 'Atlantic/Cape_Verde',
- 'Atlantic/Faroe',
- 'Atlantic/Madeira',
- 'Atlantic/Reykjavik',
- 'Atlantic/South_Georgia',
- 'Atlantic/St_Helena',
- 'Atlantic/Stanley',
- 'Australia/Adelaide',
- 'Australia/Brisbane',
- 'Australia/Broken_Hill',
- 'Australia/Darwin',
- 'Australia/Eucla',
- 'Australia/Hobart',
- 'Australia/Lindeman',
- 'Australia/Lord_Howe',
- 'Australia/Melbourne',
- 'Australia/Perth',
- 'Australia/Sydney',
- 'Canada/Atlantic',
- 'Canada/Central',
- 'Canada/Eastern',
- 'Canada/Mountain',
- 'Canada/Newfoundland',
- 'Canada/Pacific',
- 'Europe/Amsterdam',
- 'Europe/Andorra',
- 'Europe/Astrakhan',
- 'Europe/Athens',
- 'Europe/Belgrade',
- 'Europe/Berlin',
- 'Europe/Bratislava',
- 'Europe/Brussels',
- 'Europe/Bucharest',
- 'Europe/Budapest',
- 'Europe/Busingen',
- 'Europe/Chisinau',
- 'Europe/Copenhagen',
- 'Europe/Dublin',
- 'Europe/Gibraltar',
- 'Europe/Guernsey',
- 'Europe/Helsinki',
- 'Europe/Isle_of_Man',
- 'Europe/Istanbul',
- 'Europe/Jersey',
- 'Europe/Kaliningrad',
- 'Europe/Kiev',
- 'Europe/Kirov',
- 'Europe/Lisbon',
- 'Europe/Ljubljana',
- 'Europe/London',
- 'Europe/Luxembourg',
- 'Europe/Madrid',
- 'Europe/Malta',
- 'Europe/Mariehamn',
- 'Europe/Minsk',
- 'Europe/Monaco',
- 'Europe/Moscow',
- 'Europe/Oslo',
- 'Europe/Paris',
- 'Europe/Podgorica',
- 'Europe/Prague',
- 'Europe/Riga',
- 'Europe/Rome',
- 'Europe/Samara',
- 'Europe/San_Marino',
- 'Europe/Sarajevo',
- 'Europe/Saratov',
- 'Europe/Simferopol',
- 'Europe/Skopje',
- 'Europe/Sofia',
- 'Europe/Stockholm',
- 'Europe/Tallinn',
- 'Europe/Tirane',
- 'Europe/Ulyanovsk',
- 'Europe/Uzhgorod',
- 'Europe/Vaduz',
- 'Europe/Vatican',
- 'Europe/Vienna',
- 'Europe/Vilnius',
- 'Europe/Volgograd',
- 'Europe/Warsaw',
- 'Europe/Zagreb',
- 'Europe/Zaporozhye',
- 'Europe/Zurich',
- 'GMT',
- 'Indian/Antananarivo',
- 'Indian/Chagos',
- 'Indian/Christmas',
- 'Indian/Cocos',
- 'Indian/Comoro',
- 'Indian/Kerguelen',
- 'Indian/Mahe',
- 'Indian/Maldives',
- 'Indian/Mauritius',
- 'Indian/Mayotte',
- 'Indian/Reunion',
- 'Pacific/Apia',
- 'Pacific/Auckland',
- 'Pacific/Bougainville',
- 'Pacific/Chatham',
- 'Pacific/Chuuk',
- 'Pacific/Easter',
- 'Pacific/Efate',
- 'Pacific/Fakaofo',
- 'Pacific/Fiji',
- 'Pacific/Funafuti',
- 'Pacific/Galapagos',
- 'Pacific/Gambier',
- 'Pacific/Guadalcanal',
- 'Pacific/Guam',
- 'Pacific/Honolulu',
- 'Pacific/Kanton',
- 'Pacific/Kiritimati',
- 'Pacific/Kosrae',
- 'Pacific/Kwajalein',
- 'Pacific/Majuro',
- 'Pacific/Marquesas',
- 'Pacific/Midway',
- 'Pacific/Nauru',
- 'Pacific/Niue',
- 'Pacific/Norfolk',
- 'Pacific/Noumea',
- 'Pacific/Pago_Pago',
- 'Pacific/Palau',
- 'Pacific/Pitcairn',
- 'Pacific/Pohnpei',
- 'Pacific/Port_Moresby',
- 'Pacific/Rarotonga',
- 'Pacific/Saipan',
- 'Pacific/Tahiti',
- 'Pacific/Tarawa',
- 'Pacific/Tongatapu',
- 'Pacific/Wake',
- 'Pacific/Wallis',
- 'US/Alaska',
- 'US/Arizona',
- 'US/Central',
- 'US/Eastern',
- 'US/Hawaii',
- 'US/Mountain',
- 'US/Pacific',
- 'UTC']
+
+with open(os.path.join(_tzinfo_dir, 'zone.tab')) as zonetab:
+    common_timezones = [l.split()[2]
+            for l in zonetab
+            if l != '' and l[0] != '#']
+common_timezones.extend(
+        ['GMT',
+         'US/Alaska',
+         'US/Arizona',
+         'US/Central',
+         'US/Eastern',
+         'US/Hawaii',
+         'US/Mountain',
+         'US/Pacific',
+         'UTC'])
+
 common_timezones = LazyList(
             tz for tz in common_timezones if tz in all_timezones)