The Aichelburg Forest Castle stands in the heart of the woodland in the mountainside of Světlá hora mountain. Two traditional transport ways used for collecting lumber on horn sledges in the past run to it from Temný důl. The forest castle was built in 1861 as a memorial of an enlightened land owner, Berchtold Aichelburg. Inside the restored great hall there is a well-preserved bust of him to see as well as the entrance to the watchtower to find as well as other things of interest.
In the information centre Veselý výlet located in Pec pod Sněžkou or in Temný důl it is possible to borrow the keys to enter the castle on your own. The hiking trail heading to Velká Úpa from Temný důl (Dark Valley) or vice versa is very well-marked in the map as well as in the terrain. Local highlights along with historical events are pointed out in quatro-lingual texts written on en-route panels. Cross a mixed forrest via Aichelburg, past the meadow enclave Velké Tippletovy boudy chalets (Large Tippelt Chalets) with original local architecture, via Vlašské boudy chalets to Velká Úpa.