One of the most identifiable garden designs, known as the Charbagh (or Chahār Bāgh), consists of four quadrants most commonly divided by either water channels or walkways, that took on many forms.[3] One of these variations included sunken quadrants with planted trees filling them, so that they would be level to the viewer.[3] Another variation is a courtyard at the center intersection, with pools built either in the courtyard or surrounding the courtyard.[3] While the Charbagh gardens are the most identified gardens, very few were actually built, possibly due to their high costs or because they belonged to the higher class, who had the capabilities to ensure their survival.[3] Notable examples of the Charbagh include Balkuwara Palace[4] and Madinat al-Zahra in Spain.[3]