Black holes appear to come in three varieties: supermassive black holes and galactic black holes have been studied for decades, while intermediate-mass black holes have only recently been discovered (and, in fact, the discovery is still under scrutiny). No matter the size, black holes are an ideal laboratory for studying general relativity in extreme environments that cannot be reproduced in a laboratory. Constellation-X will have the ability to study all classes of black holes. Find out more about the types of studies Constellation-X will conduct in the following articles: