The lakes are actually individual sinkholes that have merged over time due to the dissolution of underlying gypsum bedrock.
The water in the lakes frequently changes color, ranging from milky green to deep blue, influenced by specific microorganisms.
The observation tower's shape was inspired by the form of a Viking-era boat or a traditional regional canoe.
The Biržai region is one of the few places in Europe where active karst formation is visible on the surface.
The tower stands at a height roughly equivalent to a 10-story building.
Some of the sinkholes in this area are estimated to be several centuries old, while new ones still occasionally emerge.
The Kirkilai Lakes and Observation Tower features a unique landscape formed by the collapse of gypsum layers, resulting in a cluster of over 30 small, water-filled sinkholes. The observation tower is designed to resemble a canoe or a traditional boat, rising 32 meters above the surrounding karst terrain. It provides a panoramic view of the interconnected lakes which often exhibit changing colors due to the growth of sulfur-oxidizing bacteria. This region is part of the Biržai Regional Park, characterized by active karst processes that continuously reshape the local topography. Visitors can traverse wooden boardwalks that wind through the wetlands, allowing close proximity to the sensitive aquatic ecosystem. The site is a prominent feature of the Biržai Karst Region, which is noted for its geological instability and unique sinkhole formations.
The top observation deck offers a 360-degree view of the scattered lakes and the surrounding agricultural plains.
Bring binoculars to better observe the birdlife inhabiting the marshy shorelines.
Wear insect repellent during the summer months, as the standing water attracts mosquitoes.
Walk the full length of the boardwalks to see the different vegetation zones surrounding the sinkholes.
Stepping off the marked paths, as the ground in this karst region can be unstable and prone to sudden collapse.
Stay on the designated boardwalks to protect the fragile wetland soil and prevent erosion of the sinkhole edges.
