The Zbrašov Aragonite Caves were declared as a national nature monument in 2003 on an area of 7.74 hectares. The subject of the protection is a representative section of hydrothermal karst territory and lies on the left bank of the Bečva river with the Zbrašov Aragonite Cave system, surface and underground karst phenomena including cave decorations, mineral water sources, resurgences of carbon dioxide and natural communities on the surface and underground.
The majority of the protected area is forest-covered with a near-natural tree species composition. The natural forest types for this locality are beechwoods with limes and oaks or lime-maple stands. The current forest stands are dominated by beech (Fagus sylvatica), sessile oak (Quercus petraea), hornbeam (Carpinus betulus), sycamore (Acer psedoplatanus) and ash (Fraxinus excelsior) but we can also find conifers such as Norway spruce (Picea abies) and silver fir (Abies alba) and other tree species. More than 220 vascular plant species have been recorded here, including many significant and protected plants such as the western polypody fern (Polypodium interjectum), martagon lily (Lilium martagon), broad-leaved helleborine (Epipactis helleborine) and hairy brome (Bromus ramosus).
The specific environmental conditions in and around the caves create suitable conditions for the existence of a range of significant and endangered animal species. The Zbrašov Aragonite Caves are not a suitable hibernating site for bats (Chiroptera) due to the high temperatures in the caves all year round. However, the lesser horseshoe bat (Rhinolophus hipposideros), common pipistrelle (Pipistrellus pipistrellus) and serotine bat (Eptesicus serotinus) bats can sometimes be seen in the area. Other specially protected animals which live at the monument include the slowworm (Anguis fragilis), sand lizard (Lacerta agilis), fat dormouse (Glis glis), sparrowhawk (Accipiter nisus) and collared flycatcher (Ficedula albicollis). Of the invertebrate groups on the territory which have been researched, the most significant group are the Diplopoda, including the millipedes Brachychaeteuma bradae and Geoglomeris subterrannea, both of which were recorded for the first time in the Czech Republic at this locality.
The Zbrašov Aragonite Cave is the only show cave in the Czech Republic which is of hydrothermal origin and consists of a complicated network of passages, chambers, chimneys and fissures at several elevations. A total of 1240 metres with a difference in elevation (denivelation) of 55 metres have been discovered and mapped so far (2008).
This is the largest known cave system in the Hranice karst region, which lies on the border of two major European geomorphological units, the Bohemian Massif and the West Carpathians and helps to explain the exceptional geological development of the locality. In addition to the usual atmospheric (surface) water, strong springs of hot mineral waters rising up along geological faults contributed to the youngest phases of karst formation in these Devonian limestones. This led to the formation of a cave with unique secondary decorations and microclimate, which is like no other cave in Europe.
In addition to the classic calcite decorations we can also find the mineral aragonite in the cave, which is a rare rhombic modification of calcium carbonate (CaCO3), which crystalizes here in the warm air conditions. A sinterball coating has developed on the walls around the mineral water lakes and reminds us of doughnuts, with a distinctly belted appearance in cross-section. The “raft stalagmites” (formerly known as geysir stalagmites) which develop on the bed of the lake as accumulations of sinter crusts which sank to the lake bottom after previously floating on its surface are a rarity on a world-wide scale.
The specific microclimate in the Zbrašov Aragonite Cave is characterised by the high air temperature in the caves (14-16°C) and the existence of spaces which are permanently filled with carbon dioxide (CO2). This gas is released from the acidulous waters of the underground lakes and hangs above their surfaces as a gas pillow several metres thick. As CO2 is 1.5x heavier than air it remains in the lowest cave levels – in the “gas lakes”.
The Zbrašov Cave was named after the village of Zbrašov as the cave lay in the parish of this village when it was discovered by the brothers Josef and Čeněk Chromý in 1912-1913. Now the cave lies on the territory of the town of Teplice nad Bečvou.The caves have been open to the public since 1926. The visitors’ route was completely reconstructed between 2003 and 2005. A connecting tunnel was dug out to allow visitors a circular tour and the latest technology was installed to enhance the visitors’ experience of visiting these exceptional caves. The visitors’ route is 275 metres long and the guided tour takes 50 minutes.
The Hůrka hill with the Hůrka u Hranic NNR, which includes the Hranická propast Abyss – the deepest abyss in the Czech Republic, lies on the opposite bank of the canyon-like valley of the Bečva river.