Gotthard Base Tunnel, a mammoth railway system constructed through the Swiss Alps, is now open after 17 years in the making.
It opened with a flamboyant opening ceremony, with dancers putting on a dramatic performance inside the tunnel entrance in Erstfeld.
Measuring 57km in length, the Gotthard Base Tunnel is the longest tunnel system in world, allowing trains to complete a journey from Zurich to Milan in two hours 50 minutes, 1 hour less than the current rail networks.
1,000 people have been selected for the maiden voyage of the tunnel , which has been financed entirely by the Swiss government at a cost of around CHF103 billion.
Even though the tunnel is 8,0000 feet beneath the Alpine peaks in some parts, it has been designed so the tracks are almost completely flat throughout, allowing trains to travel at up to 150mph.
The link will be essential for connecting the densely-populated communities of north west Europe with the south and east of the continent, allowing people and goods to be transported much faster.
260 freight trains and 65 passenger trains are expected to pass through the tunnel when it officially opens for business in December.
For those who simply can't wait til then, the clever clogs behind the construction of the tunnel have created a 360 virtual video tour to give you an idea project's huge scale.
For more underground adventure, be sure to check out the Sonnenberg tunnel tours, where you can explore the world’s largest civilian fallout shelter.
The Null Stern hotel museum is also another underground attraction that makes you marvel at Switzerland's subterranean systems.
And our secret bunkers feature to glimpse Switzerland's more secretive bunkers and underground structures.