Bardenas Reales is a semi-desert in Navarre, Spain whose vegetation and rocky formations created by erosion are unique in Europe. It covers 45,500 hectares of terrain, and its most famous sight is the Castildetierra.
In 1999, the Bardenas Reales was named as a natural park, in response to the large influx of tourists throughout the 1990s. On 7 November 2000, UNESCO declared it a Biosphere reserve. Since 1951, the Spanish air force have maintained a base in the Bardenas Reales, which quickly raised local opposition, and demonstrations against military activity occur regularly [].