The open star cluster Pismis 24 is in the nebula NGC 6357. It has some of the largest stars known. Pismis 24-1 has nearly 300 times the mass of the Sun. It is a multiple system of at least three stars.
The strange shapes taken by the clouds are a result of the vast radiation emitted by these huge, hot stars.
This image combines image data with three different filters in visible light from the 1.5-metre Danish telescope at the ESO La Silla Observatory in Chile.

The Crab Nebula, remains of a supernova that was first seen around 1050 AD