The geyser is one of the few cold-water geysers in Europe and the only one of its kind in Slovakia.
The borehole reaches a depth of 404 meters below the surface.
The water ejected is highly mineralized and has a constant temperature of approximately 14 to 18 degrees Celsius.
During peak activity, the water column can reach heights of up to 20 meters.
The park was established in the 19th century as a landscaped garden for the clients of the Herľany spa complex.
The geyser has been declared a National Natural Monument in Slovakia.
The intervals between eruptions have historically ranged from a few days to several weeks, making synchronization difficult.
The CO2-driven mechanism is geologically distinct from the thermal, steam-driven eruptions found in places like Yellowstone.
Park Herľany is the site of a unique cold-water geyser located in a historical arboretum in Eastern Slovakia. The geyser is a man-made phenomenon triggered by a deep borehole drilled in 1870, originally designed to supply mineral water for a local spa. Unlike volcanic geysers, it is powered by carbon dioxide pressure forcing cold mineralized water to the surface. The park grounds feature a collection of rare, century-old exotic trees planted during the nineteenth century. Eruptions are sporadic and the interval between them depends on natural CO2 accumulation, often leading to unpredictable timing. The park serves as a protected cultural monument due to its technical, geological, and botanical significance.
From the elevated path facing the geyser fountain, which provides a clear view of the water jet against the trees.
Check the official municipal website for the latest eruption forecasts before starting your trip.
Bring a waterproof jacket, as the spray can be unpredictable depending on the wind.
Explore the entire arboretum to see the rare tree species that have survived for over 100 years.
Do not assume the geyser will erupt just because a group of people is waiting; check the official schedule projections.
Eruptions are sporadic and occur based on natural pressure buildup; there is no fixed daily schedule.
Stay behind the designated barriers, especially during an eruption, to avoid mineral-rich water and potential slippage.
