R136a1 is one of the most massive stars known, located in the R136 star cluster within the Large Magellanic Cloud. It has an estimated mass of about 315 times that of the Sun, making it a prime example of a very massive star. R136a1 is also extremely bright, emitting thousands of times more light than the Sun. This star is classified as a Wolf-Rayet star, which means it is in a late stage of stellar evolution characterized by strong stellar winds and high temperatures. R136a1 is expected to end its life in a spectacular supernova explosion, contributing to the formation of new stars and elements in the universe.