1.Gotthard Base Tunnel, Switzerland:

The crown jewel of engineering prowess, the Gotthard Base Tunnel in Switzerland has a length of 57.1 kilometres, making it the longest railway tunnel in the world.

2.Seikan Tunnel, Japan:

The Seikan Tunnel, connecting the Japanese islands of Honshu and Hokkaido, is a marvel of underwater engineering. This 53.85 kilometer long tunnel is built under the Tsugaru Strait.

3.Channel Tunnel:

A symbol of European unity, the Channel Tunnel connects France and the United Kingdom under the English Channel. There are three different tubes in this 50.45 kilometer tunnel.

4.Yul Hyeon Tunnel, South Korea:

Located in South Korea, the Yulhyeon Tunnel is a 50.3 kilometer engineering masterpiece.

5.Songshan Lake Tunnel, China:

The Songshan Lake Tunnel in China demonstrates the country's growing engineering capabilities. This 38.813 km long tunnel is part of the Dongguan–Huizhou Intercity Railway.

6.Shenzhen Hong Kong Tunnel:

The Shenzhen Hong Kong Tunnel symbolizes the close connection between mainland China and Hong Kong. This 35.655 kilometer long tunnel allows high-speed trains to travel between the two cities.

7.Lötschberg Base Tunnel, Switzerland:

Another engineering marvel in the Swiss Alps, the Lötschberg Base Tunnel is 34.576 kilometers long.

8.New Guanjiao Tunnel, China:

Located on the Qinghai-Tibet Railway, the New Guanjiao Tunnel in China extends for 32.645 kilometers.

The Guadarrama Tunnel in Spain is a 28.418 km marvel of engineering. It is part of the high-speed rail line connecting Madrid and Valladolid.