Messier 81, also known as Bode's Galaxy, is a spiral galaxy located about 12 million light-years away in the constellation Ursa Major. It is one of the brightest galaxies in the night sky and is easily visible through small telescopes. This galaxy has a diameter of approximately 90,000 light-years and contains a supermassive black hole at its center. Messier 81 is part of a group of galaxies that includes Messier 82, a nearby starburst galaxy, and they are often studied together due to their proximity and interaction.