The Glass House Mountains are a cluster of thirteen hills that rise abruptly from the coastal plain on the Sunshine Coast, Queensland, Australia. The highest hill is Mount Beerwah at 556 metres above sea level, but the most identifiable of all the hills is Mount Tibrogargan which from certain angles bears a resemblance to a gorilla facing east towards the ocean. The Glass House Mountains are located near Beerburrum State Forest and Steve Irwin Way. From Brisbane, the mountains can be reached by following the Bruce Highway north and taking the Glass House Mountains tourist drive turn-off onto Steve Irwin Way. The trip is about one hour from Brisbane. The Volcanic peaks of the Glass House Mountains rise dramatically from the surrounding Sunshine Coast landscape. They were formed by intrusive plugs, remnants of volcanic activity that occurred 26–27 million years ago. Molten rock filled small vents or intruded as bodies beneath the surface and solidified into land rocks. Millions of years of erosion have removed the surrounding exteriors of volcanic cores and softer sandstone rock.