Oslo, Norway, is the world's second-most expensive city. Getty Images.

Americans have an average summer vacation budget of $1,180 per person, according to a recent survey by American Express. Sounds like a hefty chunk of change, right? ABC News reported on four vacations that amount of money can buy. Not one of destinations below was on that list.

If your vacation budget far exceeds the average American's, a world of possibilities are open to you. A new study from TripAdvisor.com ranks the world's most expensive cities based on four criteria: The price of a hotel room, the price of cocktails and dinner for two and the price of a round-trip taxi ride.

London ranks as this summer's priciest destination, and it's no wonder. As the host of the 2012 Summer Olympics and a barrage of recent media coverage of the Queen's Diamond Jubilee, the city is on everyone's hot list right now.

New York was the only U.S. city to make the top 10, coming in sixth. Although the average hotel rate in Boston is actually higher than than New York, it's those added expenses, like a taxi and a night on the town, that can take a bite out of the budget.

"For American travelers planning city trips, it's important to have an understanding of the day-to-day destination expenses," said Brooke Ferencsik, director of communications for TripAdvisor.

So which other cities made the top 10? Here's the list:

1. London
2. Oslo, Norway
3. Zurich
4. Paris
5. Stockholm
6. New York City
7. Moscow
8. Copenhagen, Denmark
9. Sydney
10. Singapore