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 Bridge station by Network Rail. It has a ticket hall and entrance area with its main frontage on Tooley Street, and other entrances on Borough High Street and within the main line station concourse. It is one of two mainline London termini south of the River Thames, the other is Waterloo. The Underground station is on the Jubilee line and the Bank branch of the Northern line. Several London Buses routes, including 43 and RV1, pass the station; some via the bus station. River buses use the nearby London Bridge City Pier. London Bridge station was opened on 14 December 1836, making