On Thursday, when he tours El Reno Federal Correctional Institution in Oklahoma, Barack Obama will become the first American president to visit a federal prison while in office.
But this won’t be his first visit to a prison of any kind.
In 2013, President Obama toured South Africa’s notorious Robben Island, where Nelson Mandela was imprisoned for 18 years. (Obama also toured the former prison in 2006, when he was a senator.) President Bill Clinton likewise toured Robben Island, in 1998. Mandela escorted Clinton and his wife, Hillary, through the prison corridors and into his cell.