Please answer the following question: Fort Abercrombie in North Dakota was an American fort established by authority of an act of Congress March 3 1857. The act allocated twenty-five square miles of land on the Red River in Dakota Territory to be used for a military outpost but the exact location was left to the discretion of Lieutenant Colonel John J. Abercrombie. The fort was constructed in the year 1858. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
Answer:
Building