Why the Grand Paris Express is Europes Biggest Infrastructure Project

The Grand Paris Express is one of Europes biggest infrastructure project. The project consists of new rapid transit lines and the extension of existing lines being built in the Île-de-France region of France. The project comprises four new lines for the Paris Métro, plus extensions of the existing Lines 11 and 14. This will cover a total of 200 kilometres (120 mi) of new tracks and 68 new stations are to be added, serving a projected 2 million passengers a day. We explore what it takes to build a mega project like this under one of Europe's biggest cities.