The Gornergrat (; ) is a rocky ridge of the Pennine Alps, overlooking the Gorner Glacier south-east of Zermatt in Switzerland. It can be reached from Zermatt by the Gornergrat rack railway (GGB), the highest open-air railway in Europe. Between the Gornergrat railway station () and the summit is the Kulm Hotel (). In the late 1960s two astronomical observatories were installed in the two towers of the Kulmhotel Gornergrat. The project Stellarium Gornergrat is hosted in the Gornergrat South Observatory.