A tunnel is an underground or underwater passageway, dug through the surrounding soil and enclosed except for entrance and exit, commonly at each end. In the whole wide world, different countries have different types of tunnels with various purposes either for military purposes, utility purposes or traffic purposes and these tunnels are of varying lengths. In here is the generalization of the 5 world longest tunnels.

According to Cnn, ranking first is the Gotthard Base Tunnel (GBT) having an average length of 57km running between Erstfeld town in the north and Bodio town in the south. The tunnel was opened in June 2016 aiming at improving transportation capacity between Germany and Italy through cutting travel time for passengers moving from Switzerland to Italy. Good news for speedy trains with speed of 250km per hour can use only 20 minutes to complete the whole tunnel.

Having changed Europe's geography and promote high-speed rails, Channel tunnel is the second longest tunnel of about 50km and 37.9km of the undersea section. The tunnel built by both English and French connects the UK and the other Europe continent and has entrances in both UK and France.

Laerdal Tunnel in Norway is the road longest tunnel with a length of 24.5km.the tunnel has subsections after every 6km to eliminate the tedious element to drivers. You can drive through the tunnel for 20 minutes.

As reported by Railway-technology, Tokyo Bay Aqua-Line in Tokyo has about 14km in which 4.4km is more of a bridge and the rest is a subsea conduit. The tunnel successfully connects two cities Kawasaki and Kisarazu whose travel time is reduced from 90 minutes to 15minutes. When traveling across the bay there is a mall built on an artificial island that gives a good view of the bay.

The fifth ranking tunnel is the world highest having a height of 3,401 meters above the sea level named Eisenhower road tunnel, Colorado with 2.72 km length. Spiralen road tunnel in Norway is one of the cheapest tunnels in the country but built from good engineering skills. The tunnel has a length of about 1.65 km and comprises six spirals covering 1,649 meters which are viewpoints.