The architecture of this monument, the only one of its kind in the world, tells a fascinating story. It is living testimony to the Muslim and Christian faiths. The mosque was built from the 8C to the 10C on the site of the Visigothic Church of St Vincent. After the Reconquista, it was dedicated to the Catholic religion, and, in the 16C, the Christians built a Gothic cathedral inside, right in the middle of its arches, and by enclosing one in the other they created one of the most original buildings in the world.