Founded by Spanish conquistadors on the ruins of Tenochtitlan, the ancient capital of the Aztec empire, Mexico City is the capital of Mexico, the second-largest city in the world, and one of the most polluted. Its rapid growth has been largely unplanned, leading to monumental urban challenges. Sprawling shantytowns lack basic services. Water demand has drained underground aquifers, and the city has sunk, resulting in widespread structural damage. Waste disposal is an increasing problem. The divide between rich and poor is very marked. Crime is a major concern; the rate of kidnappings here is among the highest in the world. But Mexico City's potential is enormous, the surrounding country is rich in natural resources, and the population is young and energetic. Major initiatives are being put in place to tackle the city's problems for the 21st century. ""Mexico City"" offers an all-encompassing look at this vast megacity, from its mestizo heritage, a blend of native and Spanish influences, to its phenomenal economic growth.