Discovered by Pierre Méchain in 1781.
M101 is also known as the Pinwheel Galaxy. It is one of the brightest of the Grand Design Spiral galaxies and can be viewed with modest amateur telescopes. It lies in the Constellation Ursa Major and its distance has been determined by measurements of Cepheid variable stars using the Hubble Space Telescope to be 24 (+/- 2) million light years from the earth. This "face on" galaxy is truly an impressive object.
1http://www.seds.org/messier/m/m101.html