List of longest tunnels

Columns: Type | Name | Location | Length | Year | Comment
Metro | Guangzhou Metro Line 3 | Guangzhou , China | 60,400 m ( 37.5 mi ) Excl . branch | 2005-2010 | Guangzhou Metro . Longest metro/rapid transit tunnel | Railway Twin Tube | Gotthard Base Tunnel | Central Swiss Alps , Switzerland | 57,104 m ( 35.5 mi ) and 57,017 m ( 35.4 mi ) | 2016 | Longest railway tunnel ; by geodetic distance ( of 55.782 km ( 34.661 mi ) ) between the two portals , it is also the world 's longest transit tunnel . Total 151.84 km ( 94.35 mi ) of broken out tunnels through solid rocks | Metro | Beijing Subway Line 10 | Beijing , China | 57,100 m ( 35.5 mi ) | 2008-2012 | Beijing Subway | Railway Single Tube | Seikan Tunnel | Tsugaru Strait , Japan | 53,850 m ( 33.5 mi ) | 1988 | 74 m ; longest railway tunnel until 2016 . Longest tunnel with an undersea section . Undersea section measures 23.3 kilometres ( 14.5 mi ) | Water supply | Želivka Water Tunnel | Central Bohemian Region , Czech Republic | 51,075 m ( 31.7 mi ) | 1972 | 5 m | Railway Twin Tube | Channel Tunnel | English Channel , United Kingdom / France | 50,450 m ( 31.3 mi ) | 1994 | Second longest railway tunnel until 2016 . Longest underwater section , longest international tunnel ( 2×45 m + 1×18 m ) | Railway Single Tube | Yulhyeon Tunnel | Seoul Capital Area , South Korea | 50,300 m ( 31.3 mi ) | 2016 | 107 m

Example questions:
How long is the River Arpa - Lake Sevan tunnel that is situated at an altitude of 1,900 m ? | What is the length of the Delaware Aqueduct which was built between 1939 and 1945 ? | What is the length of the second longest tunnel in the world , the Päijänne Water Tunnel ? | What is the length of the Mass Rapid Transit ( Singapore ) , Downtown Line ?

Answers:
48,314 m ( 30.0 mi ) | 137,000 m ( 85.1 mi ) | 120,000 m ( 74.6 mi ) | 43,700 m ( 27.2 mi )