Biržai Regional Park
Biržai Regional Park covers in northern Lithuania near its border with Latvia. It was established in 1992 to preserve a distinctive karst landscape. About 20% of its area is covered by forest.
The park is notable for its sinkholes, created by the dissolution of the gypsum underlying its soil. About 9,000 sinkholes have been identified; the most notable is the Karves uola, which is about 20 meters deep. In 1998 the use of pesticides and fertilizers in the area was restricted.Footnotes
