A point at which the curvature of spacetime becomes infinite. Singularities can form — for example — when too much matter is squeezed into a region which is too small. Singularities are found at the center of a Black Hole, at the beginning of the Universe in the Big Bang, and at the end of the Universe (if it ever comes) in the Big Crunch. Many scientists believe — though there is no solid evidence — that all singularities in the present Universe lie hidden behind Event Horizons. This is the "Cosmic Censorship Conjecture".