Located in Paris's famed Montmartre district, the Moulin Rouge is the most famous cabaret in the world and has entertained revellers for 120 years. Home to the French cancan, it recruits the best dancers, who wear the best costumes. Each show requires 1,000 costumes at a budget of €4 million. Some of them are the most expensive in the world, due to their feathers. We go behind the scenes with dancer Olga.