NPP Kamenná slunce

The Stone Sun National Natural Monument is a geological formation located in the Protected Landscape Area of the Czech Central Highlands, about one kilometre southeast of the village of Hnojnice in the Louny district of the Ústí nad Labem region, on the road No.249 from Libčevs to Libochovice. The object of protection is a freely accessible former small quarry, the exposed section of which proves that explosive volcanic activity took place here in the past. There is an exposed rock wall on which strange structures similar to children's drawings of the sun are visible - hence the name Kamenná slanunce.

In the past, the site was used to mine volcanic tuff, which was used as an admixture for bricks produced in a nearby brickyard. The remains of this brickworks can be found to the west of the site. This is a so-called Maar structure, which was formed during an ancient volcanic eruption. The eruption of molten magma created a funnel-shaped throat that was gradually filled with volcanic eruptions and rock fragments from the crater wall. The rock fragments were cooler than the surrounding volcanic magma and became cooling centres. The surroundings of these fragments cracked due to the unequal cooling rate and formed imaginary sunrays. The total number of visible large stone suns is about fifteen, in addition to dozens of smaller stone suns. The number and size of the exposed suns make the protected area unique on a global scale. A second similar site is located about 5 km north of here, about 250 m northwest of the village of Staré.

The site can be easily reached from the road connecting the villages of Libčeves and Koštice or by a dirt road leading from the village of Hnojnice.