M33, The Triangulum Galaxy is quite small compared to its big apparent neighbor M31.

M33 is located in the constellation Triangulum, and at 3 million light years it is the most distant object which can be seen without any optical aids (from a very dark location).
The Triangulum Galaxy is the 3rd largest member of the Local Group of galaxies.
This group includes our own Milky Way Galaxy, M31 (Andromeda Galaxy) and approximately 30 other smaller galaxies.