Ukraine sinkholeREUTERS/Pavel RebrovA car in a sinkhole in the road outside the Crimean capital Simferopol on Sunday.

Sinkholes are scarily common, and although some are small and harmless, others open gaping holes in the ground that could swallow entire buildings — or passing cars.

Recently, a sinkhole that formed in the middle of a highway in Crimea killed six people traveling in a car that fell into the hole.

Sinkholes occur when bedrock made of limestone or other carbonate rock is eaten away by acidic groundwater or a surge of pressure caused by heavy rain or burst pipes. Sinkholes happen, sometimes suddenly, all over the US and across the world where the bedrock is susceptible — notably in China, Mexico, and Papua New Guinea.

The most dangerous chasms are the ones that cause parts of cities to collapse abruptly, and we’ve put together some of the best pictures of sinkholes devouring streets, sidewalks, and buildings all over the world.