Tourists tend to avoid regions of the world with wars, civil violence and unstable domestic politics. However, stakes rise and fall. Tourism began declining in Brazil in the mid-1980's for several reasons, including concern of visitors over personal safety. Annual revenue from tourism has dropped by about $500 million in recent years and the number of tourists by about half a million in the past decade. For two weeks during the Earth Summit in June 1992, Rio de Janeiro again became the tourist paradise. When the government leaders left, so did the security and police patrols. Violent gangs swept the Copacabana beach in October, scattering tourists and snatching their belongings. These scenes were televised around the world. In 1993, the murder of a UK tourist in Florida raised the level of concern over that very popular tourist destination, with the result that holiday reservations immediately fell. Kenya's reputation as a safe, secure holiday destination was damaged in the early 90's by a number of well-publicized attacks on visitors, including one murder in the popular Masai Mara game reserve. In 1994 the IRA targeted London Heathrow airport in order to demonstrate its vulnerability in anticipation of the tourist season; 47 million passengers pass through the airport each year.