Proper noun
the Hanoi Hilton
(US, military, slang, historical) Hỏa Lò Prison in Vietnam, where prisoners of war were held.
North Vietnam was also known for its inhumane and abusive treatment of American POWs, most notably in Hỏa Lò Prison (aka the Hanoi Hilton), where severe torture was employed to extract "confessions". Source: Internet
He parachuted to safety and tried to escape via the Ma River but was quickly outnumbered by North Vietnamese troops and was taken to Hoa Lo Prison, nicknamed the “Hanoi Hilton”‘ by POWs. Source: Internet
Lee Ellis recounts his time as a prisoner of the infamous Hanoi Hilton. Source: Internet