It is located along the gorge of Radulja stream under the ascent where there are ruins of Klevevž castle. The cave has a 209m long passage which is filled with sediments at the bottom. The cave is dry but at the bottom there's a little bit of mud and it's one of the longest caves in this area. In the cave they found stalagmites and stalactites and even the prehistoric ceramics. According to the legend there was a hidden treasure inside the cave. For the moment it is still not prepared for the visitors.
Around 10m below the Upper cave of Klevevž there is the Lower Klevevž cave or the Ajdovska cave with a hypothermal spring. It flows in from a crevice in the wall with a temperature of 21°C. The cave is until this day known as the only thermal spring cave. They have searched through 518 passages already, but even this cave isn't prepared for visitors. It is interesting also for its rich cave animal life. They found colonies of the Mediterranean horseshoe bat and the mouse-eared bat, and individual lesser and greater horseshoe bats.
Radulja is just a few ten km long stream, the left affluent of the river Krka. Its upper flow, in a shorter but wild canyon with almost vertical shores, creates smaller loud and noisy waterfalls and jumps. Radulja gorge which is about 100m high begins along Klevevška Toplica. This is where Radulja cuts in deep in the lane of triad limestone and defeats the river slope in numerous smaller waterfalls that are caught up in ice during cold winter, but are quite loud in spring and fall. After the noisy rapids of Radulja they also named the nearby Klevevž, since Klingenfels actually means »the singing waterfalls«.
In the final part of the gorge there is a shorter affluent along the right bank of Radulja. Its spring comes out under a big rock and is trapped in a smaller pool. This is the hypothermal spring called Klevevška Toplica with a temperature from 21°C to 25°C. It came out at the same fracture as the spring of Šmarješke Toplice. Klevevška Toplica spring is also appropriate for swimming.
The swampy valley, where Radulja stream magically flows, the locals named Zdravci. The valley along Radulja presents the bottom of the former bay of Pannonia sea. Most probably later there was a lake here. This area along Radulja, which at strong rain crosses the banks and floods the plain, gives shelter to some rare birds and animals such as grey and white herons, otters, beavers, crawfish, deers, foxes, wild rabbits and pheasants. There are also a lot of botanical species here. The area is at some places entirely swampy, full of sedge and rush. In the areas with the wettest soil full of smaller bays you may also see reed. Along Radulja there are willows hundreds of years old that have grown all through the area and give the landscape a unique look.