1-2,Mexico City

Populated by over 26 million people, Mexico City is one of the largest cities in the world. Despite this, its historic centre is eminently walkable. A stroll from the cathedral will soon reveal colonial churches, fascinating museums and well-restored municipal buildings. Look out for the slope: Mexico City was built on a drained lake and as a consequence, many of the city’s oldest buildings have sunk unevenly into the soft soil.