Treasure-hunting volcanic hike on the rocks of Bárna

Itinerary:

• We start from the main street of the village, Kossuth Street, heading south on Béke Street following the K (Kohász Blue) trail, which turns right at the first opportunity and soon leaves the village past the calvary.
• At the nearby intersection, we follow the K▲ trail turning right, which, passing by the bivouac shelters, climbs steeply to reach Nagy-kő.
• Before the summit, at the spot indicated by the information board, take an approx. 100-meter detour on an unmarked path to the abandoned quarry!
• The K▲ trail diverges a few steps before the Nagy-kő summit; be careful when stepping out onto the rock plateau!
• We descend on the K▲ trail to the K trail and turn sharply left.
• We follow the K trail to the K+ fork. Here we will return to the village at the end of our route following the K trail, but now we follow the K+ trail.
• A 2.3 km stretch along the ridge leads straight to the Kis-kő, already marked by the geopark information board.
• We can climb steep, rocky paths from the cave up to the Kis-kő summit.
• The different character Szér-kő ridge north of Bárna is easiest reached by walking back towards the village from Kis-kő and descending on an unmarked but clear forest cart road - basically following an unofficial but visible green stripe trail - down to Bárna.
• This brings us right to the northern end of the village at the bus turning circle, from where we quickly reach the village main street, turn right, and follow the K▲ trail heading towards the summit (this is also the route we will take back to the village).

Detailed description of the route

From Bárna hidden in the depths of the forest to Nagy-kő

Even the asphalt road winding through dense forests forming a green tunnel leading to the settlement nestled in the valley surrounded by the summits of Szér-kő ridge, Nagy-kő, Kis-kő, and Szilvás-kő hints at the special location and atmosphere of this mountain village. Not to mention that the easternmost bastions of Medves area's spectacular and unique basalt volcanoes are here, which consequently are less visited than, for example, Somoskő or Salgóvár but compensate by hiding extraordinary geological formations. In short, Bárna is definitely a good choice if you plan a quiet, scenic weekend rich in hikes. While the route is passable in both directions, it might be more practical first to climb Nagy-kő, then visit Kis-kő, which is the center of the locally protected area known as Kincsrejtő Szilaspogonyi Kis-kő, and finally Szér-kő ridge.

Leaving the village on the well-marked Kohász Blue trail and passing the calvary, we ascend. From the calvary, there is a beautiful view of the village, so making this short detour is worthwhile. At the nearby intersection, we turn right following the K▲ trail, and soon on the left, two unusual small structures appear: simple wooden bivouac huts set up by local initiative where, with the right equipment, you can spend the night. From here the K▲ trail takes a steep climb to the 520-meter-high summit. Just before the summit, the Novohrad-Nógrád Geopark information board draws attention to a short 100-meter unmarked detour leading to Nagy-kő's special quarry. While basalt cones and the vast lava cover of the Medves plateau were mined in many places in the past, this quarry is something different. The huge boulders found here were formed by a rockfall, so essentially, we see a talus slope from which valuable stone was quarried. This unique, moss-covered rocky place is definitely worth visiting.

Be cautious reaching the summit as the rock is quite exposed. Nagy-kő is a characteristic Medves volcanic plug, meaning that at today's summit, we find hard basalt lava trapped in the volcanic conduit. The top of the mountain was mined earlier, resulting in a stage-like formation on the rock plateau. The quarrying was, of course, not for treasure hunting like at nearby Kis-kő but for valuable basalt, which was previously one of the most important road-building stones. Nature lovers exploring the lesser-known mountains will find a real treasure in the practically "civilization-free" panoramic views of Nagy-kő. Below us is a hunting lodge near Bárna, several villages appear in the distance under the majestic ridges of Mátra as seen from here, and on clear days, the Bél-kő landscape scar also gleams. The seemingly endless forested ridges of the Felső-Tarnai Hills and Vajdavár region make truly breathtaking views.

On the far side of the summit, the K▲ trail descends steeply and then turns sharply left onto the familiar K (Kohász Blue) trail, and we follow this pleasant contour path to the K+ fork. Here we could return to the village on the K trail, but we continue on the K+ trail. Along the ridge, the path leads straight for 2.3 km to Kis-kő, already marked by the geopark information board (there are several more boards near the summit and even a small forest rest area where we can snack).

The treasure-hiding Kis-kő

Like the basalt cones of Medves, Kis-kő is also a volcanic plug, the remnant of a volcano active about 2-4 million years ago, from which the softer crater made of volcanic debris eroded, leaving only the hard volcanic plug, the volcanic conduit. Its almost perfectly circular volcanic shape and steep sides suggest that a fortress might have once stood on Kis-kő at the dawn of history, although no serious fortifications were built later.

This basalt cone's real geological sensation is Hungary's largest vertical lava cave formed in basalt rock. The 15.6 m deep and only 30 m long cave opening naturally to the surface was formed during the eruption due to a gas bubble trapped in the basalt, scientists explain. According to folk belief, Turks hid treasure in this special but hard-to-access cave that widens downward, and supposedly, the entrance was marked by a head carved into the rock. Many treasure hunters visited the cave over time but, of course, no one succeeded. The treasure hunt even escalated to the point where a local landowner, one Géza Kemény, commissioned local miners around 1909–1910 to dig a horizontal adit over several months into the hard rock leading to the cave.

Of course, the treasure was not found even then, but we can safely explore the real treasure, the cave itself. Moreover, the information board at the rock wall draws our attention to other curiosities, such as megacrystals visible in the rock face. Since spectacular crystals are not typical for rapidly cooled extrusive rocks like basalt, these large crystals visible to the naked eye likely originate very deep, straight from the magma chamber.

Carefully climbing to the 379-meter-high summit offers a unique panorama, as this smaller peak is amphitheater-like embraced by the higher forested ridges and peaks of the area.

A completely different world: the sandstone of Szér-kő

From Kis-kő, we walk back a good distance on the K+ trail until the unofficial but clearly visible green bar trail turns right onto a wide forest cart road. Gradually descending here, we arrive at the northern end of Bárna, at the bus turning circle. From here, the village main street is just a few steps away, where we turn right onto the K▲ trail coming from the village center.

Szér-kő is a fine example of the unique sandstone rock formations of the Medves-Vajdavár area (remember that sandstone can also be found underneath volcanic cones and basalt plateaus). Here we find the so-called glauconitic, “loaf-shaped” sandstone (speckled with harder sandstone blocks) formed in a shallow sea, usually cemented by carbonate binder, which allows it to stand even on a cliff face. Along the way, we again encounter geopark information boards that tell us, among other things, how the mysterious cannonball-like spherical stones were formed. At some points of the Medves-Vajdavár area, surprisingly regular spherical rocks can be seen.

To understand their origin, let's travel back about 25–30 million years when there were no volcanoes here yet, and the former sediment basin was covered by sea water. Fine-grained sand was deposited in protected shallow marine areas, fairly evenly in some places. The shells of calcareous animals also ended up in the sand, so millions of years later, during the rock formation process, the calcium carbonate (CaCO3) content of the shells seeped out spherically in all directions. Later, this carbonate precipitated within the rock forming a regular spherical shape. The third phase of formation was when the carbonate-rich rock, more resistant to erosion, peeled off as stone spheres out of the softer environment.

Unfortunately, the view from the summit is heavily limited, but from among the trees, we can still glimpse the beautifully situated houses of Bárna, and the Mátra ridge viewed from here, looking higher than in reality, provides a picturesque background. We return to the village by the known route. If we have the strength, upon reaching the village houses, it is worth sharply turning back onto Szérkő Street and walking a little up the dirt road alongside the stream to admire the sandstone formation up close.