Several exting quaternary volcanoes are situated in the surroundings of the town Bruntál. Most of them belong to the group of mixed volcanoes, which means that the activity of the volcanoes was in turns explosive and extrusive. Lava was vomited during the surface in the shape of incoherent volvano eruptive rock. On the contrary by the extrusion lava was running out from the crater and formed the lava streams. The volcano eruptive rocks form mostly the volcano maar.

Velký Roudný / Big Roudný 780 m above sea and Malý Roudný / Small Roudný 771 m above sea

Velký Roudný (Big Roudný) is the highest volcano of the Low Jeseníky Mountains. This volcano was last active 1 – 2 milion years ago. 

Big a Small Roudný form two remarkable peaks above the village Roudno. From three lava streams of Big Roudný the northeaster one is the longest and the quarry for whinstone mining was made here. This lava stream dammed up the valley of the river Moravice in the place of todays Slezska Harta, so a great lake was formed. To which the eruptive rocks were falling. 
  
They created sediments of sponge puff-stones, which are today found in the surroundings of the villages Razová and Karlovec. These puff-stones were mined as a good building material. 
TABThe Bruntál volcanoes create a remarkable and striking feature of the Low Jeseniky Mountains countryside. 
Trip to Big Roudný

TABThe easier way to Big Roudný is from the going to Křištanovice. We will go along the guidepost from the upper crossing in Roudno. We are on the top in half an hour, where a big information board is placed and next to it there is a cone hollow, which is considered to be the rest of the crater. A rebuilt small chapel is placed on the top. Behind the chapel there are 15 pictures of the Station of the Cross on the stands. If we go downhill, we come to two stony mounds with a cross – to the victims of the 1st Word War in 1914 – 1918. More ambitous tourists can go down from the mound maybe 30m downhill to a visible road which goes out from the forest and go on along a meadow path at first to the southern direction and then turn down the way to the road to Bílčice.