How do sinkholes swallow entire houses and cities? - Elise Cutts

It was a rainy December morning in San Francisco’s Sea Cliff neighborhood when the Earth opened up.

The ground suddenly fell away into a 12-meter-deep sinkhole that engulfed a garage, part of a street, and a luckily unoccupied multi-million-dollar mansion.

Sinkholes can seem to strike out of nowhere, collapsing roads or even whole city blocks in a flash.

And they’re more common than people often think.

For example, there are tens of thousands of sinkholes in the US state of Florida alone, which range from less than a meter to over 100 meters wide.

Sinkholes form when something carves away space underground.

And in nature, that something is usually water.