France is building the world's most expensive road

Nearly 9,000 kilometres from Paris, France is building one of the world’s most expensive roads… in the ocean. On the remote island of Réunion, this vast megaproject is designed to replace a dangerous coastal route threatened by rockfalls, cyclones and crashing waves, with a 5.4km offshore viaduct at its heart.

But it hasn’t gone to plan. Costs have soared past €2BN, key materials have run short, and a crucial section is still missing, turning an ambitious solution into one of the most complex and controversial road projects on Earth.