Hoa Lo Prison was built by the French colonial administration in 1896, originally to hold Vietnamese political prisoners. Its name means "fiery furnace" — a reference to the stove-makers' workshops that once occupied the land. For the first half of the 20th century it held Vietnamese anti-colonial activists, including many future leaders of the Democratic Republic of Vietnam, in conditions that were brutal even by colonial standards. The guillotine used for executions is still on display.
The prison is best known internationally as the place where American pilots shot down over North Vietnam were held during the air war of the 1960s and 70s. American prisoners renamed it the "Hanoi Hilton" with bitter irony — conditions for POWs included torture, isolation, and prolonged captivity, though the Vietnamese government disputed this then and now. Most of the original prison complex was demolished in the 1990s to make way for the Hanoi Towers hotel complex; only the front section survives as a museum. That survival is itself telling: the French-era front gates and gatehouse were preserved, while the cell blocks where Americans were held were largely torn down. What remains is worth an hour of careful attention.