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
Hielanman's Umbrella the bridge were also upgraded. In 2001, a new entrance to the burgeoning Arches nightclub and restaurant complex was added under the bridge which has led to the level of pedestrian footfall increasing markedly. Hielanman's Umbrella The Hielanman's Umbrella () is a landmark in the centre of Glasgow, Scotland. It is the local Glaswegian nickname for the glass walled railway bridge which carries the platforms of Glasgow Central station across Argyle Street. Due to the forced displacement of people during the second phase of the Highland clearances in the 19th century, 30,000 highlanders who spoke Scottish Gaelic but not English