Basement storage in Houghton, Michigan

The Annex Building, located in Houghton, Michigan, United States, was originally connected to the AOB by a second-floor bridge. Built during the Depression for general storage and expanded library space, the Annex was designed by Wilfrid Polkinghorne, a Michigan Tech alumni. The building, constructed in 1936, may have been funded through federal New Deal programs or other sources. The interior of the Annex shows a distinct hierarchy in detailing on each floor, with the basement originally used as a rifle range for ROTC, the ground floor for general storage, and the second floor for library stack space. After various uses over the years, the Annex was eventually turned over to the archaeology program in 1977. The signature bridge between the AOB and the Annex was removed in the mid-1980s for reasons that are still unclear. Today, the Annex Building houses a water-quality testing lab for the Michigan Department of Health and other clients.