The science of SINKHOLES: Video uses toy cars and sand to show how the dangerous events can swallow vehicles

sudden big holes opening in the Earth can spell danger for passing cars - if a driver is unlucky enough to fall into one, he or she may be seriously hurt or killed.

sudden big holes opening in the Earth happen because of the interaction between water beneath the ground and soil wearing away - a process that moves soil and rock.
A new video shows/tells about how and why (sudden big holes opening in the Earth) form, and while they're sometimes caused by natural processes, many sinkholes are human-created.

A video on YouTube's Practical Engineering channel, presented by (designer of roads, bridges, etc.) Grady Hillhouse, explains how wearing away at the subsurface can lead to (sudden big holes opening in the Earth).
Wearing away can happens via wind, landslide and scrape/injury, but none of it compares to just the movement of water.
'Water is the great wear awayr,' says Hillhouse.
'If you ever find yourself wondering 'how did this particular feature of the earth come to be here?' or 'why is the ground like so, or just 'why are things the way that they are?' more often than not, the answer is pretty much just water.