In Mercer's annual survey on the most expensive cities in the world (courtesy of Fortune), Los Angeles slides all the way down to 42nd place from 29th a year ago. NY was 15th from 10th. Those were the only two North American cities to crack the top 50 (SF was 54th; Toronto 82nd). Mercer uses the cost of living in NY as as base, taking into account, housing, transportation, food, clothing, household goods and entertainment. For L.A., housing must have been a big factor in its top-50 status. So what's the world's most expensive city? Check the jump.

For the second year in a row, it's Moscow (a whopping 34.4 percent more expensive than NY) where a luxury two-bedroom rents for $4,000 a month and a CD costs $24.83. London is second most expensive, up from No. 5 a year ago and 26 percent more expensive than NY. In both cases, the weaker dollar has a lot to do with those higher costs.

MOST EXPENSIVE CITIEES
1. Moscow
2. London
3. Seoul
4. Tokyo
5. Hong Kong
6. Copenhagen
7. Geneva
8. Osaka
9. Zurich
10. Oslo
11. Milan
12. St. Petersburg
13. Paris
14. Singapore
15. New York City
16. Dublin
17. Tel Aviv
18. Rome
19. Vienna
20. Beijing

Source: Mercer