The first thing you should know before you arrive in Mexico City is that it isn't - Mexico City that is. As far as locals are concerned the name of the town is Mexico. The country was named after the city not the other way around so if you hear any of the city's 20 million inhabitants talking about Mexico they mean their hometown and not the country that they refer to as La Republica

It's an impressive setting: one of the largest metropolises in the world suspended 2,239 metres (7,394ft) up in the cloud-filled Valley of Mexico between three volcanic peaks. It was the Aztecs that recognised the potential of this lofty locale at the beginning of the 14th century. They built on an island in a shallow lake joined to the shore by a series of causeways and canals and called their new settlement 'Tenochtitlan'. Two hundred years later the Spanish conquistador Hernan Cortes razed the Aztec city and built the bones of Mexico City around a huge central square. Since then it's never stopped growing and today it could quite comfortably engulf a city the size of New York with room to spare.