The sphagnum moorland termed as Lake Nyírjes was explored by Imre Máthé and Margit Kovács in 1957. In 1961 it became a nature reserve. It was formed in the 2-3 m deep basin of the north-east slope of Darnó hill. In the middle of the lake there is a sphagnum moor with rare species. Their natural value lies in the fact that sphagnums require special microclimate so they are very rare in Hungary. The lake is continuously being refilled and reed needs greater and greater areas. It can be reached by following the blue + symbol off the blue symbol in the main street of Sirok from the centre and it takes approximately two kilometres.