6. Dusseldorf, Germany
German city Dusseldorf fell one spot from last year's rankings to take the sixth spot in 2012. However, the city has made Mercer's top 10 rankings for the best quality of life for the past six years.
The city by the river Rhine is the seventh most populated in Germany and is renowned for its fashion and trade fairs. With more than 100 galleries, Dusseldorf is Germany's art capital.
Dusseldorf's high standard of living is a big draw for the ultra-wealthy. The city ranks second only to Munich for the highest population in Germany of people with a net worth $30 million or more at 1,380, according to research firm Wealth-X. Earlier this year, local media also reported that the city has more millionaires than any other German city.