Kirkilai Karst Lakes

Northern Lithuania sits on gypsum, which dissolves in groundwater, and the Biržai district is the most active karst area in the country: sinkholes open in fields and roads, sometimes suddenly, and thousands have been recorded. At Kirkilai a group of them filled with water, producing a cluster of small round lakes separated by narrow ridges, and a wooden observation tower and boardwalk let you see the pattern from above, which is the only way to make sense of it. The area continues to develop new holes. Signs around the district warn about the ground. It is a short and unusual stop, easily combined with Biržai castle and the town's breweries, and it takes under an hour.

What you actually see

• Sinkhole lakes - small round waters separated by narrow ridges.
• The observation tower - the wooden platform giving the overhead view.
• The boardwalk - the path threading between the holes.
• Active karst - ground that is still collapsing across the district.

When to go

May to October for the walk and the greenery; autumn colour improves the view from the tower. The site is open at all times. Winter access is possible but the boardwalk can be icy.

Honest expectations

The site is small and the visit is short. The lakes are modest in size and the effect depends on getting up the tower. Interpretation is limited. There are no facilities beyond a car park.

Nearby

Biržai and its castle lie east.