thumb|The Gotthard Base Tunnel is the first flat route through a major mountain range. The Thirlmere Aqueduct in North West England, United Kingdom is sometimes considered the longest tunnel, of any type, in the world at , though the aqueduct's tunnel section is not continuous. The Dahuofang Water Tunnel in China, opened in 2009, is the third longest water tunnel in the world at length. The Gotthard Base Tunnel in Switzerland, opened in 2016, is the longest and deepest railway tunnel in the world at length and maximum depth below the Gotthard Massif. It provides a flat transit route between the North and South of Europe under the Swiss Alps, at a maximum elevation of . The Seikan Tunnel in Japan connects the main island of Honshu with the northern island of Hokkaido by rail. It is long, of which are crossing the Tsugaru Strait undersea. The Channel Tunnel crosses the English Channel between France and the United Kingdom. It has a total length of , of which are the world's longest undersea tunnel section. The Lötschberg Base Tunnel in Switzerland was the longest land rail tunnel, with a length of , from its inauguration in 2007 until the completion of the Gotthard Base Tunnel in 2016. The Lærdal Tunnel in Norway from Lærdal to Aurland is the world's longest road tunnel, intended for cars and similar vehicles, at . The Zhongnanshan Tunnel in People's Republic of China opened in January 2007 is the world's second longest highway tunnel and the longest mountain road tunnel in Asia, at .
thumb|The Gotthard Base Tunnel is the first flat route through a major mountain range. The Thirlmere Aqueduct in North West England, United Kingdom is sometimes considered the longest tunnel, of any type, in the world at , though the aqueduct's tunnel section is not continuous. The Dahuofang Water Tunnel in China, opened in 2009, is the third longest water tunnel in the world at length. The Gotthard Base Tunnel in Switzerland, opened in 2016, is the longest and deepest r.ailway tunnel in the world at length and maximum depth below the Gotthard Massif. It provides a flat transit route between the North and South of Europe under the Swiss Alps, at a maximum elevation of . The Seikan Tunnel in Japan connects the main island of Honshu with the northern island of Hokkaido by rail. It is long, of which are crossing the Tsugaru Strait undersea. The Channel Tunnel crosses the English Channel between France and the United Kingdom. It has a total length of , of which are the world's longest undersea tunnel section The Lötschberg Base Tunnel in Switzerland was the longest land rail tunnel, with a length of , from its inauguration in 2007 until the completion of the Gotthard Base Tunnel in 2016. The Lærdal Tunnel in Norway from Lærdal to Aurland is the world's longest road tunnel, intended for cars and similar vehicles, at . The Zhongnanshan Tunnel in People's Republic of China opened in January 2007 is the world's second longest highway tunnel and the longest mountain road tunnel in Asia, at .