The subsidence in Mexico City caused by groundwater extraction can also be seen at the cathedral in the main Zócalo Square. "When you look at the cathedral from the front, you can immediately spot that it is leaning," says Michael Schmidt, co-ordinator at Conobio, the National Commission for the Exploration and Use of Biodiversity, in Mexico City. The front part of the cathedral is standing on fine-grained sediment, and so it is subsiding. On the other hand, the rear part is standing firmly on the remains of a former Aztec temple.
Credit: josegagar (CC-SA 3.0).