Photo: GetYourGuideThe best way to make sense of the Centro Historico is on foot with a local guide, threading between the Zocalo, the ruins of the Templo Mayor, ornate colonial palaces and hidden courtyards while the layers of Aztec, Spanish and modern Mexico are unpicked around you. Wear comfortable shoes for the cobbles. It is an ideal first-morning orientation, and the guide will happily steer you towards the best nearby spot for lunch.