Mexico City is sinking so quickly, it can be seen from space

Mexico City is sinking by nearly 25 cm a year, according to new satellite imagery released this week by NASA, making it one of the world’s fastest-subsiding metropolises.

One of the world’s most sprawling and populated urban areas, at 7,800 sq. km and some 22 million people, the Mexican capital and surrounding cities were built atop an ancient lake bed. Many downtown streets were once canals, a tradition that continues in the rural fringes.