The Alhambra is Spain’s most significant and well-known Islamic architecture. M.C. Escher visited on at least two occasions and his sketches of Alhambra, along with those of his wife, informed his artwork style. According to the text Visions of Symmetry he sketched a portion of a wall in Alhambra on 0ctober 20 1922 and again between May and June 1936 he and his wife made numerous sketches.
Schattschneider, Doris. Visions of Symmetry: Notebooks, Periodic Drawings, and Related Work of M.C. Escher. W.H. Freeman and Company. New York, 1990.