A "riad" (sometimes spelled "riyad"; ) is an interior garden found in many Moroccan mansions and palaces. It is normally rectangular and divided into four parts along its central axes, with a fountain at its middle. Riad gardens probably originated in Persian architecture (where it is also known as "chahar bagh") and became a prominent feature in Moorish palaces in Spain (such Madinat al-Zahra, the Aljaferia and the Alhambra). In Morocco, they became especially widespread in the palaces and mansions of Marrakesh, where the combination of available space and warm climate made them particularly appealing. The term is nowadays applied in a broader way to traditional Moroccan houses that have been converted into hotels and tourist guesthouses.