Gotthard Base Tunnel (Rail Tunnel) Design Engineering, Construction & Cost
It is one of the most extreme engineering projects in World History, to build a 35 miles long tunnel under the Alps Mountains. It is the longest tunnel in the world. This could not be possible without world’s strongest drilling machines, each more than 3 stories high and longer than 4 football fields, drilling 24hrs a day for 6 years. The project costed $7 Billion.