When I saw the Alhambra in 2009 I was stunned. The first thing that caught my eye were the gardens; everything was so vibrant. I hadn't expected that. The second thing I noticed was the stark contrast between the Muslim and Christian architecture. For the most part, Islamic architecture is VERY ornate, and quite breathtaking. Usually carved designs or colorful tile-works line the walls and ceilings. (Only the first three photos are mine, I didn't get many shots while touring.)
Islamic artists used the stylistic elements created during the 8 centuries of Muslim rule: Calliphal horseshoe arch, Almohad sebka, Almoravid palm, and stilted arches and muqarnas (stalactite ceiling decorations). Columns and muqarnas appear in many rooms, and the interiors of the palaces are decorated with arabesques and calligraphy. When the Alhambra was reclaimed by the Christians, however, the conquerers began to alter their work. Much of it was filled up and painted over, and furniture soiled, torn, or removed. Portions were even destroyed during the Renaissance. Even so, much of it still remains today and demonstrates the level of architectural skill in Islamic architecture.