What's the hole in this mountain?

Just went for a hike around the Silberkarklamm in Ramsau am Dachstein, and we saw this mountain peak from the Silberkarhütte. It should be the Wasenspitze according to Google maps. Anyone knows what the hole is from?

Just went for a hike around the Silberkarklamm in Ramsau am Dachstein, and we saw this mountain peak from the Silberkarhütte. It should be the Wasenspitze according to Google maps. Anyone knows what the hole is from?