What is this thing we call gravity?

Very poetic, matter's longing for itself creating gravity. Can we feel it? If we'd not have gravity we'd float off into space. or have to be attached by a cord to some buried anchor, not a heavy object since weight would not exist. We could build the pyramids by merely giving the stones a mild push in the right direction. Only problem is how to keep the stones down. Perhaps the ancient builders or their instructors had devices that could switch off this effect called gravity. Any how the story goes that Isaac Newton studied this phenomenon after one apple, hurled by gravity, crashed the top of his head and being the scientist he was he started asking Why? Or was is What?