Thieves stole $500,000 watch from a man sitting outside in Beverly Hills. Why’s it worth so much?

Last Friday, local jeweler Shay Belhassen was sitting outside at a Beverly Hills restaurant when he was robbed at gunpoint by three men. They took his rose gold Richard Mille RM 11-03 Flyback Chronograph watch, which is valued at about $500,000. It’s the same watch seen on the wrists of tennis player Rafael Nadal and musician Pharell Williams. What makes it so valuable?