Move over London. Bangkok is edging out the British capital as the world's top city for tourists. That's according to new figures from Mastercard. The U.S. credit card issuer forecasts that the Asian city will get almost 21.5 million visitors this year. That's ahead of London, on just under 20 million. Paris and Dubai are in third and fourth place. Tourism is a rare bright spot for Thailand, where the economy has struggled since a 2014 military coup. A recent wave of bomb attacks in the south of the country apparently has been no deterrent to visitors. But London might yet have a trump card to play, with the value of the pound crashing by about 10 percent after the vote for Brexit, a development that has suddenly made the city a whole lot cheaper for overseas visitors.