Our starting point is the picturesque little town of Osek with its significant and dominating sight, the Romanesque Cistercian Monastery built in 1196. Unfortunately, the turbulent history of the town and the monastery is closely connected with frequent attacks and numerous raids usually ending with ransacking and town burning. However, despite this unfortunate and sad history, the historical core and the monastery were beautifully rebuilt and thanks to that we may now take advantage of the guided one-hour tour of the monastery. From the crossroad for Osek – square, the monastery, we start following the red and blue signs towards "Pod Hrádem Osek" (Under Osek Castle) (2.5 km). At the end of the village we will come to a Memorial for the Nelsonská catastrophe, which was declared a national cultural heritage monument. From the educational trail information board (hereinafter ET only) we learn that the memorial was built to commemorate 144 mine disaster victims who died at the Nelson III mine in January 3, 1934. From the memorial we take a walk through the woods, join the road and take a moderate climb /2/ through the valley of Osecký Brook through Staré město (Old town) towards the Pod hradem Osek (Under the Osek castle) crossroad. The educational trail as well as our red signs will turn right, and after a 0.5 km long climb we reach Osek Castle. The ruins of the Osek – Rýzmburk Castle are hidden on the left side of the crossroad sign and behind a house yard, around which we have to pass. It is one of the largest castle ruins in Bohemia. The castle was founded at the beginning of the 13th century but in the 16th century, when it belonged to the Lobkovic clan, it was deserted and abandoned. However, the large cylindrical tower in the lower section of the castle was repaired in the 19th century and is now almost as high as it used to be. The castle ruins are accessible at your own risk only.
After leaving the castle we take a short uphill climb. When we join a forest road we turn left and leave the red sign route and walk around the peak with the ruins of the castle on the top, until we reach the Nad Osekem (Above Osek) crossroad. From here we may take a "quick peek" at the Vrása educational trail stop, which is only 200 metres away. After a sharp but steep climb we are presented with several views of the large and cylindrical Osek Castle tower. To the left from the information board inside the forest we will see a protected rock formation called the Vrása. The vertical cliff is about 8 m high and approximately 25 m wide and has a distinctive horizontal fold in the crystalline slate, which serves as evidence of the ongoing processes that occurred during the Paleozoic period in the Krušné Mountains.
From the "Nad Osekem" crossroad we take a gradual walk down through an ancient beech forest while following the ET towards "Salesiova heights" (5.5 km). The ET will take us into a deep ravine, where two small brooks meet each other. We can also see a former mine entrance here at the 8th stop of the ET – Bat winter grounds. Now we continue mostly downhill following the slope above Osecký Brook and the road that we used earlier to reach the castle. Later, as we come out of the woods near the upper ski lift station, we will be rewarded with a nice view of the little town of Osek. This beautiful viewing post will give us a chance to enjoy the views of the picturesque area under the Krušné Mountains, facing towards the Osek monastery, also known as the pearl of the Krušné Mountains.
Shortly after that we will encounter a rock hidden in the forest. The ET – Krušnohorský crack will explain the existence of this rock to us and we will learn that it is a gneissic rock wall tilted between 60-70°. This rock wall represents the slip plane of the Krušnohorský break, separating deposits of the Tertiary period from crystalline and therefore, demonstrates the break in the earth's crust along which the platform sank down and the Krušné Mountains' platform rose up. Behind the road from Loučná to Osek near the Salesiova height we will be surprised by a rare quartz rocky town, around which the ET passes by. It is also an interesting locale from a paleontology point of view, because we can find numerous prints of cores and shells of freshwater bivalves from the Unio family. The educational trail will take us around Osecký Pond (public swimming pool) back to the town square.
Total length 10.5 km.
