The primeval valley of the Piusa River is known for its picturesque sandstone outcrops, which are called walls in the local language. The highest sandstone outcrop in Estonia is located here: the first, the Upper Härmä Wall, or Keldri Wall, a 19 m high wall that is 43 m above the valley. Following the wall 150 m further leads to a bridge over the water where one can take in views of the river valley. The second, the Lower Härma Wall, or the Kõlgusniidu Wall, is slightly lower, at 20 m, but the colors are brighter and so it is considered one of the most beautiful outcrops in Estonia. An RMK campfire site and camping site are located near the Kõlgusniidu Wall.
Piusa River Valley Hiking Trail. The trail starts 10 km from the ruins of Vastseliina Castle.