The idea of our major cities gradually sinking into the earth sounds like the plot of a science fiction movie. But research shows that some of the most densely populated urban areas in the United States, like New York City and Miami, are descending into the ground at an alarming pace.
This sinking of land, called subsidence, is happening faster now than in previous years. Both human-made and natural factors are to blame — from the impact of the ice age to the weight of our buildings.
