Opened in June 2016, the Gotthard Base Tunnel is 57.1 km long and is the longest railway tunnel in the world.
The longest Japanese tunnel is 53.9 km long with a 23.3 km portion under the seabed of the Tsugaru Strait.
Also known as Eurotunnel, it is 50.5 km long underwater tunnel that connects France and Great Britain.
Opened in December 2016, the 50.3 km railway tunnel is located in South Korea and is currently the fourth-longest in the world.
The railway base tunnel in Switzerland is 34.6 km long and connects Spiez and Brig at the northern end of the Simplon Tunnel.
Located in China, it is a dual-bored, double-track rail tunnel, that is 32.645 km long. It is the longest tunnel in China.
Located in Spain, it comprises two parallel tube tunnels, each 28.4 km long and 8.5 metres wide, and passes through the Sierra de Guadarrama mountain range.