One of the world’s largest metropolis, Mexico City is also the oldest urban centre in the Western Hemisphere, when it was called Tenochtitlán. Spanish conqueror Hernan Cortés and his men were awestruck by the sight of the imposing temples of the Aztecs. Reporting back to King Carlos V, Cortés was struggling to convey the majesty of what he saw. Imagine the King’s surprise at learning that "one of the plazas is twice the size of that of Salamanca", and "the principal pyramid is taller than the tower of the cathedral at Seville", or that the stone and wood craftsmanship that adorned these monuments "could nowhere be bettered".