The peat-bog Tříjezerní Slať (Three Lakes Fen - 5 ha) lies about 3 km north-west of the village Modrava. It was named according to the three bog-lakes, which lie in the peat-bog.

The short nature trail, which was founded in 1978, leads through the peat-bog along the duckboards. It is about 200 m long with 11 stops with informative notices about the most interesting places and about the types of peat-bogs, origin of peat and about vegetation of peat-bogs.

The peat-bog is accessible for hikers and for cyclists along the red marked path joining the yellow marked one from the settlement Antýgl (about 4 km).