The Drachenloch is a cave above Vättis in the municipality of Pfäfers in the canton of St. Gallen in Switzerland. In addition to bones of cave bears, traces were found in the cave that indicate human life more than 50,000 years ago. The Drachenloch lies at an altitude of 2427 m above sea level. M., making it the highest prehistoric site in Europe.

Between 1917 and 1923, digging took place on a total of 201 days in the summer months. Nigg was supported in work by his assistants Abraham Bonderer and Hermann Kressig, and Bächler also worked in the Drachenloch for a total of 34 days.

Even if no human skeletal remains were found, signs of a possible settlement by Neanderthals during the Palaeolithic or Mousterian were found, among other things, in the form of fireplaces and tools. The year 1766 scratched into the third cave shows that the cave had been entered long before Nigg.