This satellite image shows the military-run Saydnaya prison, one of Syria’s largest detention centres, located 30 kilometres north of Damascus. Amnesty International / AFP
This satellite image shows the military-run Saydnaya prison, one of Syria’s largest detention centres, located 30 kilometres north of Damascus. Amnesty International / AFP

13,000 hanged since 2011 in Syrian prison known as ‘the slaughterhouse’