Coddington's Nebula

Despite its misleading name, IC 2574 is a dwarf irregular galaxy roughly 4 million light-years away in Ursa Major, and a satellite of M81. Discovered by Edwin Coddington in 1898, it is riddled with enormous expanding HI supershells — holes blown into the interstellar medium by successive generations of supernovae — making it a key laboratory for studying triggered star formation.