Sitting in San Francisco Bay, a little more than a mile off the coast of downtown San Francisco, is Alcatraz Island. The Island is home to the famous (infamous) former federal penitentiary that once housed the likes of the mobster Al Capone. Alcatraz, which closed in 1963, was a maximum security prison, surrounded by shark-infested waters (not an exaggeration). No one who escaped the island was ever confirmed alive.
The island is now under the jurisdiction of the National Park Service. It is accessible by boat, operated by Alcatraz Cruises, which departs from San Francisco’s Pier 33. Alcatraz Cruises is the ONLY way to actually set foot on the island. There are several other cruise companies that will take you around the island, but will not dock.
Make sure to book your tickets ahead of time - sometimes several days or even weeks in advance. Tickets can be booked through the National Park Service’s Alcatraz website: https://www.nps.gov/alca/index.htm.
Tours of the island are self paced and include an audio device to listen to former inmate’s stories. There are also NPS Rangers and former inmates scattered around the property to answer any questions you might have.
The tour, including transit time to and from Pier 33, lasts approximately three hours. I suggest booking a night tour. The night tour is usually harder to schedule and lasts about an hour longer. It too includes the self paced audio tour, then allows for approximately two hours of self guided wandering around the grounds after the sun goes down. The night tour is slightly creepy, but there are enough other people wandering the grounds that you are never truly alone in any room, if you’re worried about that. I highly recommend it.