Before the rocky islet of Alcatraz became America’s most dreaded high-security prison in 1934, it had already served as a fortress and military jail. Surrounded by the bone-chilling water of San Francisco Bay, it made an ideal place to hold the nation’s most wanted criminals – men such as Al Capone and Machine Gun Kelly. The conditions were inhumane: inmates were kept in solitary confinement, in cells no larger than 9ft by 5ft, most without light. They were not allowed to eat together, read newspapers, play cards or even talk; relatives could visit for just two hours each month. Escape really was impossible: nine men managed to get off “the Rock”, but none gained his freedom, and the only two to reach the mainland (using a jacket stuffed with inflated surgical rings as a raft) were soon apprehended.

Due to its massive running costs, the prison finally closed in 1963. The island remained abandoned until 1969, when a group of Native Americans staged an occupation as part of a peaceful attempt to claim the island for their people, citing treaties that designated all federal land not in use as automatically reverting to their ownership. Using all the bureaucratic trickery it could muster, the US government finally ousted them two years later, claiming the operative lighthouse qualified it as active.

At least 750,000 tourists each year take the excellent hour-long, self-guided audio tour of the abandoned prison, which includes sharp anecdotal commentary as well as re-enactments of prison life featuring improvised voices of the likes of Capone and Kelly. Ferries to Alcatraz leave from Pier 33; allow at least three hours for a visit, including cruise time. Advance reservations are essential – in peak season, it’s nearly impossible to snag a ticket for a same-day visit.