Difficulty: Challenger (Level 2)

Europe’s longest tunnel for testing hyperloop technology opened last month in the Netherlands.

Operators hope the system will eventually transport passengers from Amsterdam to Barcelona, a city in Spain, in just a few hours.

In comparison, driving between these two cities currently takes about 15 hours.

A hyperloop is a proposed type of train that travels through a giant tube at a very high speed. There is barely any air inside the tube, so that means there is no friction to slow down the train (see graphic). This also makes it more energy efficient.

The testing tunnel is white and shaped like the letter “Y”. It is 420 metres long and made up of 34 interconnected pipes around 2.5 metres wide.

The European Hyperloop Centre is the world’s only facility to feature a “lane switch”, where the track splits into two paths. This allows scientists to test what happens when a vehicle changes course at high speed.

“You need [the lane switch] to create a network … so one part goes, for example, to Paris, [and] the other one heads off to Berlin,” said centre director Sascha Lamme.

Hyperloops are still being tested. Lamme said that by 2030, they should be able to transport people about five kilometres, such as from an airport to the city.