'Biggest show on earth' Paris prepares for opening ceremony extravaganza

It is billed as the biggest open-air show on eartha spectacle so ambitious it has shut down a city centre and its airspace, mobilised 45,000 police and several army units and taken two years to rehearse in secret.

- Angelique Chrisafis

When the Paris Olympics opening ceremony begins tonight, it will be the first time the theatrical curtain-raiser for the world's biggest sporting event has taken place outside a stadium.

Instead of the traditional parade around a stadium track, more than 8,000 of the world's top athletes will be transported by boat along 3.7 miles of the River Seine in a kind of sporting armada, as more than 300,000 people watch from the bridges and riverbanks and police, divers and snipers stand guard.

While the athletes glide down the river, dancers, pop stars, tightrope walkers and acrobats will perform daring feats on water, rooftops, bridges and artificial islands using pontoons, floating pianos, helicopters and potentially even submarines, before a vast laser show finale is beamed from the Eiffel Tower.

More than 1 billion people are expected to watch live on TV and social media. The idea of performing a show of this magnitude along a massive stretch of river in a city under its highest terrorism alert was so outrageous that even Emmanuel Macron at first thought it was "a crazy and not very serious idea". But this week at the Elysée, he said: "We decided it was the right moment to deliver this crazy idea and make it real."