Monaco

Monaco is a country you can walk across in under an hour, but you'd need a few lifetimes to afford most of what's in it. This 2-square-kilometer city-state squeezed onto the French Riviera between Nice and the Italian border is the most densely populated country in the world, the playground of the ultra-rich, and a tax haven that has attracted everyone from Russian oligarchs to Formula 1 drivers. The Monte Carlo Casino is the one that James Bond made famous, and the annual Grand Prix turns the city streets into the world's most glamorous racetrack.

But Monaco isn't just about money and motors. The Grimaldi family has ruled here since 1297, making it one of the oldest ruling dynasties in the world. Prince Rainier III married Grace Kelly in 1956, turning Monaco into a permanent fixture of tabloid royalty. The Oceanographic Museum was directed by Jacques Cousteau for decades. And despite the image, it's a genuinely functional micro-state with its own flag, anthem, and 38,000 residents crammed into a space smaller than Central Park.