Spring brings clear and bright colours to the valley of the Sázava River. Hikers who turn off the trail from the Český Šternberk Castle and follow the path along the river will discover a blossoming island in the local countryside. The compact greenery of coniferous woods in the arc of the river is exchanged for a mixture of broad-leaved trees. Every year dozens of the mezereon plant grow on the steep, rocky slopes of the Na Stříbrné territory. Their pink blossoms give off a strong fragrance, enticing insects just awoken from their winter hibernation. The mezereon is true to its reputation - the entire plant, including the berries, is poisonous. The colourful forest, dominated by beech trees, has escaped the attention of the foresters thanks to the unscalable steep and rocky terrain. The building stone was extracted at some places and even the miners stopped in the locality for a short time. An exploring shaft leading into the heart of the rocks was dug into the foothills of the mound in an effort to discover silver. This gave the place its name - Na Stříbrné (On the Silver). Although people left the shaft later on, it did not stay uninhabited. Several bat species have found a home here. They spend the winters in the cool underground climate hanging off the ceiling of the shaft, and following their long hibernation, they fly outside to welcome the spring and blossoming mezereons in the uphill forest.