Messier 67 is an open star cluster located in the constellation Cancer. It is one of the oldest known clusters, estimated to be around 4 billion years old, and contains over 500 stars. The cluster is approximately 2,700 light-years away from Earth. Discovered by Charles Messier in 1780, Messier 67 is notable for its relatively high concentration of stars, which are mostly similar in age and composition. This makes it an important object for studying stellar evolution and the dynamics of star clusters.