From the 8th to 11th centuries, the Mezquita was the crowning architectural achievement of western Islam. It’s a fantastic forest of arches painted with alternating red and white stripes—a realization in stone of a billowing desert tent. A Roman Catholic cathedral interrupts the vistas, as it sits awkwardly in the middle of the mosque as an enduring symbol of Christian hubris. The 16th-century cathedral may have been architectural sacrilege, but it does have an intricately carved ceiling and baroque choir stalls. One of the interesting features of the mosque is the mihrab ★★, a domed shrine of Byzantine mosaics that once housed the Qu’ran. After exploring the interior, stroll through the Patio de los Naranjos (Courtyard of the Orange Trees), which has a beautiful fountain where worshippers performed their ablutions before prayer and tourists rest their weary feet.