Ukraine conflict: What happened in Kiev's Maidan square?
On 20 February 2014, more than 50 anti-government protesters were shot dead in Kiev's Maidan square.
The massacre triggered the collapse of Ukraine's pro-Russian government, prompting Moscow to annex Crimea and sparking a separatist war in the east.
At the time, riot police were blamed for the deaths, but they were not the only ones shooting that day.
The BBC's Gabriel Gatehouse, who witnessed the shootings, returned to investigate.