Break in the tunnel at Saint Anthony Falls, 1869.

The rapids of Saint Anthony Falls in 1869, as they appeared before the break in the tunnel.

John L. Merriam, c.1865, one of the primary people responsible for the tunnel project.

Break in the tunnel at Saint Anthony Falls, 1869.

Bridge Square, Minneapolis, with the electric light mast at center, c.1884.

Lower section of the electric light mast at Bridge Square, Minneapolis, ca. 1883. The first centralized hydroelectric power in the United States turned on in downtown Minneapolis on September 5, 1882.

Description: Stone Arch Bridge, 1884.

Image of original 1878 astronomical observatory (at right).

Interior of Goodsell Observatory, showing its new telescope, 1891. Photographer: John Runk.

Architect's c.1887 drawing of Goodsell Observatory, including a small floor plan. From American Architect and Building News, no. 601 (July 2, 1887).