The 13m circular stone platform in front of St Basil's Cathedral is known as the Place of Skulls. Legend has it that it was the site of executions, including those of the Streltsy rebels. In reality, it was a stage for tsarist decrees and religious ceremonies.
Members of the Pussy Riot punk collective famously climbed it in December 2011 to record a video clip for a song called 'Putin pissed himself'.