Thermopolis sprang to life as travelers came to its hot mineral springs, and the Plaza Hotel, originally known as the Callaghan Apartments, was one of six hotels built in the park in the early 1900s to lodge people seeking access to the healing waters of the Big Spring. The two-story structure originally had 70 rooms divided into fourteen sections, each hall containing a common bathing room. James Callaghan, a master bricklayer, built kilns along the banks of the Big Horn River to fire bricks used in constructing the hotel, and he and his wife Hazel operated it for a short time after its completion in 1918. Dr. P.W. Metz purchased the Callaghan Apartments in 1921 and renamed it the Plaza Hotel and Apartments. It is the only remaining hotel in Hot Springs State Park from the era of early commercialization, and it was placed on the National Register of Historic Places in 1993 and renovated in 1999. In 1886, James McLaughlin, United States Indian Inspector, reported to the Department of the Interior that the water of Big Springs was said to possess wonderful curative properties, to benefit rheumatic and other ailments, and, despite its temperature of 132 degrees, to be pleasant to drink, tasting with salt and pepper much like fresh chicken broth. As word of the water's healing power spread, people poured into the area in search of relief from their pains.