The second wave of major construction started in 1908 when the largest structures in the fort were built, including the three-story double barracks (Bldg 36), which now houses the park superintendent's office and is used as the modern park headquarters. Another large building was the bachelor officers' quarters (Bldg 1), constructed immediately to the west, fronting the parade ground. This iconic building anchors the northwest corner of the main fort area and houses the Horace Albright Visitor Center, a museum, theater and the Yellowstone Association gift shop. Officers' row was completed with the construction of a double captains' quarters (Bldg 2) and a field officers' quarters (Bldg 3) immediately south of the bachelor officers' quarters. Cavalry stables (Bldgs 34 and 38), a double stable guardhouse and blacksmith shop (Bldg 37) were built behind these residences. All these buildings are used by the National Park Service as administrative offices, maintenance facilities or residences.