How the World's Most Remote Megaproject Went Wrong

TL;DR

Réunion Island's $2B+ coastal road stalled because a court blocked quarries needed for the dyke, and rock quantity was massively underestimated.

Key Points

• 1.Réunion's old coastal road was dangerously unsafe. Built in 1959, the Route du Littoral carried 80,000 vehicles daily between Saint-Denis and La Port, but faced cyclone winds up to 100 mph and rockfalls — including a 2006 cliff collapse that killed two people.
• 2.The new 12.5km route was engineered around two key structures. The western dyke, up to 17 metres high with layered armour rock, would absorb ocean swells, while the 5.4km Grande Chaloupe Viaduct — France's longest bridge — would carry traffic up to 300 metres offshore.
• 3.Building in isolation required extraordinary logistics. Two concrete factories were built on the island, and a specialist Polish-built barge called Zourite — the size of a football pitch — was used to install all 48 bridge piers over four years, completing the viaduct in 2017.
• 4.A court ruling against quarrying stopped the project cold. Plans for two new quarries to supply an estimated 7 million cubic metres of rock were blocked in 2018 after judges ruled they would destroy protected species habitats, leaving the dyke without its primary material source.
• 5.The rock shortfall was far worse than anyone realised. A review revealed the project actually needed 12 million cubic metres — nearly double the original estimate — and sourcing rock from South Africa was ruled out due to the 2,000km shipping cost, halting construction in 2019.
• 6.The project became one of the world's most expensive roads with work unfinished. Costs exceeded $2 billion USD with only 8 of 12.4 kilometres built; 800 accropodes were also found incorrectly installed. In 2022 the council approved finishing the route as a full viaduct, adding ~€700M, with completion now targeted for 2030.