Ollantaytambo dates from the late 15th century and has some of the oldest continuously occupied dwellings in South America. Its layout and buildings have been altered to different degrees by later constructions; for instance, on the southern edge of the town, an Inca esplanade with the original entrance to the town was rebuilt as a Plaza de Armas surrounded by colonial and republican buildings. The plaza at the center of the town also disappeared, as several buildings were built over it in colonial times.