Grand Forks’ purest example of Streamline Moderne design is the central recreation feature of historic Riverside Park. It is a symmetrical, smooth-finished concrete building with window openings visually tied together by horizontal banding. The entrance to the building is recessed and shaded by a shallow canopy with rounded corners that continues the wraparound horizontal lines. On the building’s exterior are Moderne lighting fixtures, plaques, and details associated with its WPA sponsors. The basement contained an early technologically advanced, diatomaceous earth pool filtration system that relied on organic “gravity” filtration methods rather than chemical cleaning. The Grand Forks Parks authority and the preservation community have struggled to preserve and protect this landmark feature, which has been on the unprotected “wet side” of a flood barrier since 2007.