Kaštanka is natural monument which was declared as special protection area on 1st December 1990. The set of chestnuts is on a slight rise north ward. This area is in a built-up area about 100 meters from the city square. Kaštanka is at an altitude of 472 – 486. The area of set is 1,088 hectares large and all trees are chestnut trees expect a few that are on the edge.