The Cone Nebula is an often imaged HII region in the constellation Monoceros and is about 2500 to 2700 lightyears distant.  This impressive celestial object is located at the southern end of NGC 2264 (The Christmas Tree Cluster) and surrounding nebula.  The Cone is an enormous pillar of dust and gas approximately 7 light years in length.  Radiation pressure and stellar winds of the young hot stars of the Christmas Tree Cluster are responsible for shaping the conical shape of the Cone.  The Cone resembles the Pillars of Creation made famous by the iconic Hubble image.  Pillar structures like these consist of large dense clouds of gas and dust and are stellar nurseries where new stars are forming.  The surrounding red nebula is classed as an emission nebula and is energized to shine by the intense ultraviolet radiation of the brightest member of the Christmas Tree Cluster.  This star (S Monocerotis) is located to the north and out of the field of view of the above image.

William Herschel discovered the Cone Nebula December 26, 1785.  He catalogued the Cone as H V 27.  Herschel discovered the surrounding Christmas Tree Cluster almost 2 years earlier.  Today both the Cone Nebula and the Christmas Tree Cluster share the designation NGC 2264.

¹https://www.constellation-guide.com/cone-nebula/