Sinking city.

Mexico City, which sits atop drained lake beds, is sinking at the rate of 15-20 inches a year because the groundwater table is not being replenished as fast as it is depleted, Washington Post reports.

A fascinating read. Of course, it doesn't help that Mexico City relies on groundwater for 70% for its annual water demand, which is about as much as "5 million Olympic sized swimming pools."