Top-10 World Most Expensive and Powerful Cities

London, England

Gross domestic product (2005): $452 billion
GDP (2020): $708 billion
Growth rate: 3%
MasterCard Ranking: 1
Population (2007): 8,567,000
Purchasing power (NYC=100): 92%

By 2020, London is expected to leapfrog Paris and become Europe's richest city as measured by GDP. London's 3% growth rate is high for a major city in the developed world. London is ranked as the No. 1 city on MasterCard's Centers of Commerce index, owing to the vast volume of its financial markets. It's comparable to New York in equities and commodities trading but is larger in bond and derivatives trading. The downside? It's expensive. The purchasing power of the average Londoner is less than their New York peers.

Hong Kong, China

GDP (2005): $244 billion
GDP (2020): $407 billion
Growth rate: 3.5%
MasterCard ranking: 6
Population (2007): 7,206,000
Purchasing power (NYC=100): 49%

Hong Kong benefits from its physical proximity to the Chinese mainland and its historical connection to Western markets. MasterCard ranks Hong Kong the best business center in the world, based on a composite of its ports, airports, hotels and commercial real estate development.

New York, N.Y.

GDP (2005): $1.13 trillion
GDP (2020): $1.56 trillion
Growth rate: 2.2%
MasterCard ranking: 2
Population (2007): 19,040,000
Purchasing power: 100%

In absolute terms, the economy of New York City is second only to Tokyo. In fact, there are only 14 countries in the world with bigger economies than New York. And though the city has a reputation for a high cost of living, the average New Yorker can buy more than counterparts in London, Paris, Tokyo and Hong Kong.

Tokyo, Japan

GDP (2005): $1.19 trillion
GDP (2020): $1.6 trillion
Growth rate: 2%
MasterCard ranking: 3
Population: 35,676,000
Purchasing power(NYC=100): 96%

Tokyo is the world's most populous city by the U.N.'s reckoning, and it has the largest economy. By PricewaterhouseCoopers' projections, Tokyo will still have the largest economy in 2020, though New York will be getting closer. Tokyo's huge size comes at a price: Of the 151 largest economies, its growth is expected to rank at No. 140.

Chicago, Ill.

GDP (2005): $460 billion
GDP (2020): $645 billion
Growth rate: 2.3%
MasterCard ranking: 5
Population (2007): 8,990,000
Purchasing power (NYC=100): 115%

America's second city faces stern competition from Los Angeles, which now has a larger population and a bigger economy. But Chicago still outranks Los Angeles on MasterCard's Commerce Index. The Chicago Mercantile Exchange and Chicago Board of Trade give Chicago a role in the global financial markets that Los Angeles (who still remembers the Pacific Exchange?) lacks.

Seoul, South Korea

GDP (2005): $218 billion
GDP (2020): $349 billion
Growth rate: 3.2%
MasterCard ranking: 9
Population (2007): 9,796,000
Purchasing power (NYC=100): 56%

Similar to Hong Kong, Seoul benefits from a growing Asia and Western-oriented markets.PricewaterhouseCoopers projects that by 2020, Seoul will surpass Atlanta, San Francisco, Houston and Miami in GDP.

Paris, France

GDP (2005): $460 billion
GDP (2020): $611 billion
Growth rate: 1.9%
MasterCard ranking: 7
Population (2007): 9,904,000
Purchasing power (NYC=100): 88%

Today the economy of Paris is bigger than London's. But sluggish growth in this old-world capital has it slowly losing ground. By 2020 it will have been passed by London. We'll always have Paris, yes, but by 2020 its economy will be little larger than rapidly-growing Mexico City.

Los Angeles, Calif.

GDP (2005): $639 billion
GDP (2020): $886 billion
Growth rate: 2.2%
MasterCard ranking: 17
Population (2007): 12,500,000
Purchasing power (NYC=100): 120%

Los Angeles is on course to become the world's third city with a trillion dollar economy. And while that economy will always be smaller than New York's, those in Los Angeles take solace: According to UBS estimates, the average resident of L.A. has 20% more purchasing power than their counterparts in New York

Shanghai, China

GDP (2005): $139 billion
GDP (2020): $360 billion
Growth rate: 6.5%
MasterCard ranking: 24
Population (2007): 14,987,000
Purchasing power (NYC=100): 36%

With an explosive projected-growth rate of 6.5%, the size of Shanghai's economy would more than double between 2005 and 2020. Shanghai is hardly the only Asian economy with rapid growth--in 15 years this will be a very different list. Indian cities Mumbai and Delhi are projected to grow by around 6%; Jakarta, Indonesia, by 6.5%; Beijing by 6.6%.

Toronto, Canada

GDP (2005): $209 billion
GDP (2020): $327 billion
Growth rate: 3%
MasterCard ranking: 13
Population (2007): 5,213,000
Purchasing power (NYC=100): 113.8%

Toronto only narrowly edged out Madrid, Spain; Philadelphia and Mexico City, Mexico, to hang on at No. 10. Toronto is still the economic heart of one of the world's wealthiest countries, and it's projected to keep humming through 2020. Along with London, Toronto is the fastest growing G7 financial center.