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 was demolished and replaced with a dedicated building in 1902, as part of the reconstruction of Waterloo in the early 20th century. Traffic and passengers to Waterloo increased throughout the century, and Waterloo was extended in an ad-hoc manner to accommodate this. In 1860, new platforms were added on the northwest side of the station; these were known as the Windsor Station after its intended destination. An additional dock siding of the main station opened on 17 March 1869. A link to the South Eastern Railway (SER) line from to opened in July 1865. It was diverted from London Bridge