Monaco may be the second smallest country in the world, but it is also one of the richest. Almost a third of its residents are millionaires, lured to the French Riviera city state by its lenient fiscal policy -- income tax was abolished in 1869. It is estimated that 70% of the population is foreign-born, while just 10,000 are locals, "the Monegasques."

Best months to Visit Monaco

For $1 million you can buy just 183 square feet (17 square meters) of prime property, according to the Knight Frank 2017 Wealth Report, compared to 280 square feet (26 square meters) in New York or 323 square feet (30 square meters) in London. More info.