Everybody knows a water source as a spot where natural ground water comes out of the soil. A chantoir is the reverse.
It's in fact a natural sinkhole where a small stream or forest river is disappearing fast into the dark underworld.
The chantoir in my shot is the biggest sinkhole in Belgium.
It originated about 400 million years ago, has a depth of 21 meter and finally ends into underground caves 4 km further.
Location : Sècheval (Belgium)
Now and then, the chantoir of Sècheval is explored by speleologists or should I say daredevils....... (see picture below).