Location: N56° 12` 10.0", E24° 45` 29.9"
Biržai is one of the oldest cities in Lithuania. The city is located between two rivers the Apaščia and the Agluona and two lakes: Širvėna and Kiluciai. This former Radvila city whose centrepiece and a reflection of the past is the palace of a bastion fortress. The counts Tiškevičiai left their footprints in this city in the 19th century. The city is decorated with St. John the Baptist and Evangelical Reformed Churches. Biržai is a place where people do not say a popular folk saying "Curl up and die!" even to the angriest enemy because it may come true in the literal sense. Groundwater washes soluble gypsum, dolomite, limestone formations and the land subsides, making sinkholes. There are over 9 thousand sinkholes in the district.
People of Biržai have known how to exploit the mineral resources in the treatment and how to nurture ancient brewing traditions for a long time.
Biržai Regional Park Visitor Centre. The relief structure of the reception symbolizes the constitution of a sinkhole slopes, when geological layers consisting of a variety of rocks appear after a collapse. The ceilings simulate sinkholes as well. The exhibition has installed interactive stands-games "The Development Process of Sinkholes”, “The Ecosystem of Sinkhole Lakes”. The stand, acting as an hourglass, mimics a collapse of a sinkhole, the other stands depicts sinkholes before the crash, and after the collapse, which will help visitors to understand about the ongoing natural phenomena in Biržai region. The second exhibition hall for visitors show minerals and rock exposure, introducing the geological riches of the region. Another interactive cognitive exposure stand lets visitors feel the depth of the borehole scale and know the change of geological layers.
Visitor Centre presents the exposition of the theme "The region of subsiding earth." The distance of the route is 21 km, the duration of the tour is 2.5-3 hours. Guided tours must be booked in advance by calling tel. (8 450) 32 889 or (8 450) 35 805. The guide service fees: 3 hours tour per person is 2,00 € in the Lithuanian language and 3,00 € in a foreign language. The prices are for groups consisting of at least 10 adults and 15 children or disabled persons. Smaller groups are charged: 1-9 adults in a group - 20 €; a group of 1-14 children, disabled persons - 15 €.
- Kirkilai Sinkhole Lakes. Most of sinkholes in this reserve have slumped below the ground water level and have turned into small lakes, swamps.
- “Badger’s Cave” cognitive-geological trail (5 km). An educational-geological hiking trail (total length 700 m) was set up in 2012
- Natural heritage "Cow’s Cave”. It is the best-known and best studied geological monument of national importance in Northern Lithuania.
- Smardonė spring is a hydrogeological monument of national importance. It exudes from a slightly undulating plain of a sinkhole. This spring gives rise to Smardonė stream. The local people pointed out Smardonės spring a long time ago because of its abundant water, its bitter taste and distinctive smell of hydrogen sulphide gas. The specific smell dictated logically the corresponding name. Perhaps the first news about Smardonės spring as having medicinal properties, and the use of its water is already found out in written documents of 1587. In 1938 Likėnai clinic was opened. Until there were no wells of mineral water it was drawn from springs and hence the great Smardonės spring, and it was used for baths, and diluting therapeutic mud in treating various diseases.