The Pleiades is an open cluster located in the constellation of Taurus. At a distance of only 444 light years, its one of the closer open clusters. The dust surrounding them was originally thought to be left over from their formation, but it is now thought the cluster is moving through a dusty region of space. The blueish color of the surrounding nebula comes from light reflecting off the dust.
Known since ancient times, Charles Messier added it to his list of comet like objects in March 1769, even though it would be difficult to confuse them with a comet.