Centro Historico, Mexico City.
This is Calle Moneda at the Zocalo. The leaning wall on the right is the National Palace.
Most of the street building facades in the historic Centro show signs of a serious problem, the constant sinking of the subsoil due to depletion of the aquifer below the city.
Mexico City buildings are seriously leaning because of the land subsidence. Many have saved the facade only by cutting and patching with no interior that is usable.
Home to 21 million people, who consume nearly 287 billion gallons of water each year, the city has sunk more than 32 feet in the last 60 years because 70 percent of the water people rely on is extracted from the aquifer below the city.
The water table is sinking at a rate of 1 meter (3.2 feet) per year. As the city population grows and water demand increases, the problem will only get worse.