Ciudad Encantada is one of the national parks in Spain. Its name means “enchanted city” and refers to dozens of rock formations of various shapes stimulating imagination. Some of the formations are named after objects which they resemble. Tourists may see the Roman Bridge, Mushrooms, Dog, the Stone Sea or Convent. Unusual formation of rocks results from their geological layered structure. Their upper part is built of grey-colored limestone, which erodes much slower than the upper part built of yellow-reddish limestone, which creates overhangs and ledges during the process of erosion.