A second phase of building and upgrades started in 1908 which resulted in the prominent architecture visible at Fort Yellowstone in the 21st century. Built from locally quarried sandstone, these buildings defined Fort Yellowstone. The most prominent of the structures built in the later period is the Horace Albright Visitor Center which was originally the bachelor officers' quarters (Bldg 1). Each historic building in the fort and the park was assigned an official number, with the original bachelor officers' quarters being building number 1. Architects Reed and Stem and Robert Reamer along with the U.S. Army Office of the Chief Quartermaster, Department of Dakota participated in the design of many of the facilities. Engineer facilities and landscaping were designed by Captain Hiram M. Chittenden of the U.S. Corps of Engineers.