Ūlos Akis (Ūla's Eye) is one of the most famous and impressive springs in the region, where many such natural wonders can be found. Located near the Ūla River between the villages of Mančiagirė and Žiūrai, this spring has been declared a hydrogeological natural monument. Sand continuously bubbles in the center of the spring, stirred by a strong upwelling of water — locals say the spring “is alive.” Since ancient times, Lithuanians believed spring water had special powers. People from the surrounding villages used to drink the water from Ūlos Akis and even used it for healing purposes.

Ūlos Akis lies on the left bank of the Ūla River, about 8 meters from the shore. It resembles a tiny lake — its basin is 4.4 meters long and 3.4 meters wide. In its center, a strong flow of water constantly stirs up the sandy bottom. The spring’s discharge is 2 liters per second, meaning that up to 137.2 cubic meters of water flow into the Ūla each day via a 67-meter-long stream.