If you’ve been to Cordoba you’ll know all about shape-shifting. The phenomenon by which something you love and cherish suddenly and inexplicably becomes something else entirely is probably best viewed in the city’s spectacular Mosque Cathedral. It is unimaginably beautiful and profoundly surprising because it is both Islamic and Christian. There comes a point when you’re walking through the forest of ancient and elegant Arabic pillars and arches and enter, almost imperceptibly, a Gothic, Christian interior where you’ll find a proper transept, altar and pulpit. This shift from one heavenly expression of faith to the other is spellbinding.