Below Žakýľ Castle lies Žakýlske pleso (715 m above sea level), also known locally as Morské oko (‘Sea Eye’).
The lake formed after volcanic activity ended in the Tertiary period, making it both the oldest and the only natural lake in the Banská Štiavnica area.
As the lake has no adequate inflow of water, it is covered with cyanobacteria and algal bloom, creating a local biocentre for aquatic wildlife. In 1986 Žakýlske pleso and the surrounding area were declared a natural monument, with the fourth level of protection.
The Žakýlske pleso educational trail, with nine information panels, leads to the lake. It is 7 km long with 262 m of ascent and takes about 3.5 hours. The trail is a circular route that starts and finishes at the bus stop in the village, where you can also park.
