Messier 91 is a barred spiral galaxy located in the constellation Virgo. It was discovered by the French astronomer Pierre Méchain in 1781 and later included in the Messier catalog by Charles Messier. This galaxy is approximately 38 million light-years away from Earth and has a diameter of about 100,000 light-years. Messier 91 is notable for its bright core and well-defined spiral arms, making it an interesting object for both amateur and professional astronomers.