The Thompson Block, on the southeast corner of Main and Grand. This illustration is from the promotional/ souvenir booklet "Helena Past, Present and Future", published about 1891.
The Thompson Block stood for only 25 years. It was built in 1887 by Pittsburgh-based real estate entrepreneur John Douglas Thompson (1830-1911), and was designed by John C. Paulsen, architect of the current Montana Club building and the Broadwater Natatorium. The block was demolished in 1912 to make way for the building of the Placer Hotel. One narrow storefront on the south side of the Thompson Block was also demolished for the Placer.
Illustration courtesy of Tom Mulvaney.