Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Sovereign Hotel (Oregon) - The Sovereign Hotel was a Portland Oregon hotel built in 1923. The nine story building was added to the United States' National Register of Historic Places on December 2 1981. Part of the building houses a portion of the Oregon Historical Society's Oregon History Center.
A:
Building