We've known for years that black holes produce so much gravitational pull that nothing, not even light, can escape its grasp, but we did not know that black holes can actually warp time too.
Black holes can cause things moving faster, to slow down, and then suddenly speed up again. This concept is described by a space probe in the Science Channel video above.
As black holes bend light, they also bend time. Time, like light, is relative, and can be modified just like anything else with extreme forms of gravity.
Looking at light through the gravitational field of a black hole would be like looking at light through a puddle of water where a water droplet just fell. Those rays of light are warped and bent around the gravitational pressure of the black hole itself.