The orbits of the planets around the sun is a good example. The planets are constantly circling the sun. Black holes are probably the most massive and awesome example of gravity. They cannot be seen, but the way stars and light move around black holes, we know that they are there. The Swarz Child Radius is the radial distance where light can't escape from a black hole. It is the perimeter surrounding a black hole and if anything including light goes inside that perimeter, it will be sucked in by the black holes gravity.