Portal:National Register of Historic Places/Did you know/10

...that the Lumber Exchange Building in Minneapolis, Minnesota (1885) is the oldest remaining building in the United States outside of New York City with 12 or more floors?
...that the once-buried remains of a power canal and flour mills in downtown Minneapolis, Minnesota have been unearthed and are now open as Mill Ruins Park to provide historical interpretation in the area?
...that despite shortages of money during the construction of the Deerwood Auditorium in Minnesota, the building was substantially completed in time for its first event, a lutefisk supper?
...that the Frieda and Henry J. Neils House is Frank Lloyd Wright's only work with marble walls?
...that the Thomas Wilson (pictured), a whaleback freighter, was the last such freighter built without hatch coamings?