A purpose-built brothel that opened in 1890 and ran continuously until 1982, on Mercury Street in what was Butte's red-light Venus Alley. The Dumas is now a small museum about the city's sex trade and the largely forgotten women who worked it.
Tours include the cribs, the parlour, and the basement tunnel where, at the height of the boom, miners came and went without ever appearing on the street. The building was in danger of collapse for years; a slow restoration is ongoing.