Stalagmites are the things that grow up. Columns occur when Stalactites and Stalagmites meet as in the pic on the left. Cave paintings are those barely recognizable renderings of bison or mammoths of a quality often seen in elementary school rooms or modern art museums in New York. This is what Indians did for a living before they got into the casino thing. Indians were also the first spelunkers.
Spelunkers are the idiots that explore caves for the fun of it.
There's more to it than that, but that is all you get for now. Our cave guides used to use everyday household flashlights to take tourists into our man-made stygian realm. Try having 16 of them that don't work when you need them. But then the Coleman company came through with some rechargeables and saved the day. Still, the flashlight thing eventually became tiresome, so we installed limited lighting along the trails.