Centro Histórico (Historic Centre) brims with fine colonial buildings and historic sites. Its nerve centre and the heart of Mexico City is Zócalo, the Plaza de la Constitución, which is home to the powers-that-be.

On its east side is the Palacio Nacional, built on the site of an Aztec palace. It now holds the offices of the president, a museum and historical murals by Diego Rivera. To the north of the plaza is the Catedral Metropolitana (built by the Spanish in the 1520s on the site of the Aztecs' Tzompantli). The plaza is also a stomping ground for political protesters - it's often dotted with makeshift camps of strikers or campaigners.

Also in the vicinity is the excavated Templo Mayor (Main Temple) of Aztec Tenochtitlán, thought to be on the exact spot where the Aztecs saw their symbolic eagle with a snake in its beak perching on a cactus - still the symbol of Mexico today. In Aztec belief this was literally the centre of the universe. Museo del Templo Mayor, an excellent museum within the Templo Mayor site, houses artefacts from the site and gives a good overview (in Spanish) of Aztec civilisation.