M45

In ancient times they were known as the Seven Sisters of the Pleijades, and that is how many stars a good eye can see on a clear night, grouped together tightly within the constellation of Taurus. Most people have seen them at some time or the other, consciously or not.

The view through binoculars or a telescope reveals many more hot, blue star; they are young, and remnants of the gas from which they have formed still surround them.