They were always known to the locals, as very deep springs, but exploration of them as flooded caves had to wait for the development of cave-diving to a suitable level, so perhaps from the 1970s.
blue holes are inland underwater caves that form when land collapses, creating a sinkhole.
Blue World - 2008 Blue Holes and the Georgia Aquarium 3-1 was released on: USA: 27 August 2011
Yes, they do.
They both have holes in them!!!
Yes some red an blue
Ergoregion
They were found by an American rocket: NASA and scientists found them.
Black holes can be found anywhere in space.There are 2 types of black holes.Stellar and super massive black holes.Super massive black holes can be found in the middle of every galaxy including our own milky way.Stellar black holes can be found anywhere in space.
Stories with holes are stories missing an important part .You have to figure out what the missing part isANSWER FROM ,BLUE
It is somehow connected
Yes.
Blue holes are so far down in the sea that sunlight can't hit them and that means there is no oxygen, and that means that the microorganisms can live to decay the bones and fossils.