No Escape: Dive Into a Black Hole (Infographic) by Karl Tate - When matter is compressed beyond a certain density, a black hole is created. It is called black because no light can escape from it. Some black holes are the tombstones of what were once massive stars. An enormous black hole is thought to lurk at the center of the Milky Way galaxy.
A binary black hole system, viewed edge-on. This pair of extremely dense objects twists and warps spacetime as the two black holes spiral in toward one another. Image Credit: Bohn, Throwe, Hébert, Henriksson, Bunandar, Taylor, Scheel (see http://www.black-holes.org/lensing) via: http://www.universetoday.com/116500/new-simulation-offers-stunning-images-of-black-hole-merger/
Black holes are some of the most mysterious objects in the universe — what is left behind after a star has collapsed. NASA has compiled several dramatic images of what are believed to be black holes in space.
Is Our Universe Inside Another Larger Universe? Theoretical physicist Nikodem Poplawski from Indiana University has proposed that perhaps our universe could be located within the interior of a wormhole which itself is part of a black hole that lies within a much larger universe.