Montezuma Castle cliff dwellings were built and used by the Pre-Columbian Sinagua people around 1400 AD. It was made a National Monument by president Theodore Roosevelt in 1906. Another large set of rooms once stood at the base of the castle, but have long since eroded. An eco-friendly structure by today's standards, the castle was shaded in the heat of the summer and bathed in sun light during the winter.