The Grunas Canyon, a natural monument, can be found on the south side of the Thethi park. The Grunas Canyon has vast carbon formations. The canyon is around 2 km long and 60 metres deep, and varies from 2-3 meters to 30-40 meters wide. There is an incomparable beauty and all the time there is enough water to canoe sailing fans. The water of the Thethi River is crystal clear at any time and very cold. The visits to the site are not advised without local guides or it is advisable that the visit be in groups. The Grunas Canyon was and remains a challenge for all foreign and Albanian tourists that are passionate about canyons.