Quarry below Trosky is a minor location in Kingdom Come: Deliverance II.
This used to be a quarry to help build Trosky Castle, but after it was completed, the quarry was abandoned. It's now used by a hunter, Bohumir, for an archery range.
Madman treasure[]
Note that there's a nearby location, Vagrant's hut, where a madman is known to still be digging around the quarry. Speaking with the hunter will reveal that supposedly the madman and a friend of his had stashed their savings away in a secret spot in the quarry many years ago, but only the friend knew the location. Unfortunately, the friend died from an accident, leaving the madman to try and search hopelessly for his lost money.
The money itself is real: on the left side of the quarry, against the rocky walls is a ladder. Climb up it and you should see to the left a flat area with a wooden beam sticking out over the quarry. Climb over to this area and examine the leafy pile near the tree up here to find 549 Groschen. You can either choose to keep it or go speak to the madman to return it to him for some reputation.