Alcatraz IslandThe Rock — America's most famous former federal prison, on its own island in San Francisco Bay, reached by ferry from Pier 33

Alcatraz began as a Civil War–era fortress and military prison, but it earned its legend as a federal penitentiary between 1934 and 1963 — the end of the line for inmates who caused trouble at other prisons. Its location did the work the walls couldn't: a mile and a quarter of cold, fast bay current that the government believed no one could swim. Al Capone served time here, as did George 'Machine Gun' Kelly and Robert Stroud, the 'Birdman of Alcatraz.'

The centerpiece of a visit is the Cellhouse audio tour, widely considered one of the best in the world — narrated by former guards and inmates, it walks you cell block by cell block through D-Block solitary, the mess hall, the library, and the recreation yard, telling the daily-life and escape stories as you go. The 1962 escape of Frank Morris and the Anglin brothers — who left papier-mâché dummy heads in their bunks and were never found — is reconstructed at the very cells where it happened.

Beyond the prison, the island is a national park and a surprising wildlife refuge: nesting seabirds, tide pools, and gardens once tended by inmates and staff. It's also a site of Native American history — the 1969–71 Occupation by the group Indians of All Tribes left graffiti still visible today. Dress in layers (it's windy and cold offshore), wear good shoes for the steep climb to the Cellhouse, and book your ferry well ahead.