The caves serve as the main resurgence for the Brenta River basin's karst aquifer.
The name 'Covolo' is a regional Venetian term for a natural cave or cavern.
The water exiting the caves maintains a stable temperature of 9 degrees Celsius year-round.
Archaeological finds have confirmed the caves were utilized by humans since prehistoric times.
The resurgence is fed by the plateau of the Seven Communes (Altopiano di Asiago).
The cave system includes a sophisticated monitoring station for seismic and hydrologic research.
The Grotte di Oliero are a complex of karst river caves located in the Brenta Valley, characterized by an underground resurgence of the Oliero River. Visitors access the site via a guided boat trip that navigates the calm, subterranean lake waters. The site features the 'Covolo dei Siori' and the 'Covolo degli Assassini', names derived from historical local usage. The caves maintain a constant internal temperature of approximately 12 degrees Celsius throughout the year. The surrounding park area is a protected natural environment featuring botanical gardens and native flora. Water emerging from the cave system is famously clear and historically significant for local mills and irrigation. The site is a key destination for studying karst phenomena in the Veneto region.
The wooden dock area where the boat tours begin, capturing the contrast between the turquoise cave water and the limestone entrance.
Bring a warm sweater or light jacket due to the consistent low temperatures inside the caves.
Wear non-slip, closed-toe shoes as paths near the water can be damp.
Combine the cave visit with a walk through the adjacent Parco Naturale delle Grotte for the best botanical views.
Do not attempt to access the unguided areas or the restricted upper levels of the karst system.
Closed during the winter months; check for seasonal opening schedules starting from early spring.
Maintain silence during the boat tour to respect the cave environment and local wildlife; do not touch the stalactites or cave walls.
