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Mount Nanos: the rock which blocks the road to the sea

Home > Slovenia travel tips > Nature areas in Slovenia > Mount Nanos: the rock which blocks the way to the sea

Mount Nanos in southern Slovenia is a mighty piece of rock which, for many centuries, forces travellers to take a detour.

Blocking Travellers

At least since the Roman times, traders have travelled through what is now Slovenia. This is the logical route around the Alps from Vienna and Prague in central Europe over Maribor and Ljubljana to the Mediterranean sea. When you are almost there, there is one last obstacle which forces you to take a specific pass underneath it: Mount Nanos. West of Postojna, it raises high above the surrounding landscape as a massive piece of limestone rock. Everyone who has travelled to the Adriatic sea has certainly seen it. Few take the time to explore the mountain though.

The Difficult and the Easy Way Up

In spite of the steep limestone cliffs, which form the sides of Nanos, there are several trails which lead to the top. Some are rather steep and only for experienced climbers but there is an easy one which leads through the forest. there is also one for cheaters, which is asphalted so you can drive all the way up. Actually, with groups of naturalists, I sometimes decide to take this asphalted one. This leaves us more time to explore the higher parts of Nanos, which stretch out as a mighty Karst plateau. On my own, I take the easy forest trail equally often.

Beware of the Weather!

Nanos is a serious mountain: it is advised to check the weather forecast before planning a trip over the upper plateau. Up there, you are exposed to all weather influences. This includes the Burja, the freezing cold mountain wind which accompanies changes in the weather.

Traditional use of the Nanos plateau is largely abandoned, and we now find a mosaic of old grassland, bushes and young trees as well as Pine plantations. 

Grazing Formed the Landscape

The upper part of Nanos is a wide open space, slightly undulating and with fantastic views. This area shows traces of its former use: while it is below the natural treeline, natural forest is largely lacking. For centuries, grazing with sheep and cattle has been practised here. During the last century, this grazing was largely abandoned on most of Nanos. However, there is still a smaller part of the area which is extensively grazed with cattle. In some of the more sheltered parts, there used to be small fields for cabbage and other vegetables. Inhabitants of the nearby Vipava valley used to grow these because their living area is in summer too hot and dry in summer.

Natural Succession shapes a Mosaic Landscape

When the traditional land-use stopped, some parts of Nanos were planted with Pine, but most of the upper part of Nanos is nowadays not in use. Natural vegetation succession is taking over and we now find a mosaic of old grassland, bushes and young trees.

Some parts of Nanos are floristically rich and in early summer, an endemic form of the Siberian iris flowers here.  

Flora and fauna of Nanos

In the Slovenian Karst, there are a number of areas which were traditional use has been abandoned. As long as no fertilisers have been used, these places have a rich flora with many flowering plants. Nanos is nowadays progressing to the next stage in the vegetation succession; there are large expanses of dense grass which no longer hold as many flowers as they used to. Forest edges are now more interesting: here we find the former richness of the area in its full glory. Wild Paeonies and three species of Iris stand out because of their large size. Blue Flax is common and the unpalatable Asphodel grows even on the grazed part of the mountain.

Many butterflies

These flower-rich forest edges are also the best places for butterflies. On good days in early summer, it is still possible to find over fifty species of butterflies here in a single day! Common and Scarce Swallowtail are both common, and we can see numerous Frittilary species here. Nanos is the Slovenian stronghold for the Black Ringlet, which reaches the northwestern limit of its distribution here. Other ringlets are more numerous, and you can expect to see Woodland Ringlet and Scotch Argus.

Especially on the edges of the forest, you can find many butterfly species, including this Soothy Copper. 

Grasshoppers and Mantis

Especially in more barren, open places, there are many different grasshopper species on Nanos. The Large Banded Grasshopper stands out because of its bright colours and large size. Somewhat earlier in the season, in early summer, you might find Bull-bushcrickets which have a remarkably diverse song. They are flightless and don’t jump much, but appear to be continuously on the move. Like many parts of southern Slovenia, Nanos is a good area to observe Praying Mantis.

Birds of Prey

With its wide expanses of half-open and open terrain, Nanos is an excellent place to observe birds of Prey. Besides common species like Buzzard, Kestrel and Sparrowhawk, you may see Golden Eagle and Peregrine Falcon. Sadly, Rock Partridge is long extinct on Nanos. Actually, there are very few pairs of this species left in the whole of Slovenia. Rock Bunting and Cirl Bunting are still common, and around the rocky slopes, there is a good opportunity to see Blue Rock Trush. In the early morning, and at sunset, you may be lucky to see small groups of Chamois grazing in the open areas.  


Large Banded Grasshoppers stand out because of their size and bright colours. They are just one of many grasshopper species which occur on Nanos.