Bulgaria–United States relations to work. Bulgaria became a member of the Warsaw Pact on May 14, 1955. Though no Soviet troops were stationed on Bulgarian soil, in 1968, Zhivkov sent a Bulgarian division to join Polish, Hungarian and Soviet troops to crush a popular uprising in Prague. In 1978, the Bulgarian secret police were implicated in the assassination in London of Georgi Markov, a Bulgarian dissident who was a correspondent for the BBC World Service, Deutsche Welle radio and the U.S. sponsored Radio Free Europe. Markov was assassinated with a poisoned umbrella on September 7, Zhivkov's birthday. The rise of democratic movements across
London Waterloo station which commemorated World War I. Waterloo was the last London terminus to provide steam-powered services, which ended in 1967. The station was the London terminus for Eurostar international trains from 1994 until 2007, when they were transferred to St. Pancras International. Waterloo is the busiest railway station in the UK. It is also the country's largest station in terms of floor space and has the greatest number of platforms at 24. When combined with the Underground and Waterloo East stations, it is the busiest station complex in Europe. The station's formal name is London Waterloo, and appears as such on