Planina Disappearing Lake

Imagine a big summer meadow at least 6km long, bursting with trees, birds, butterflies & wild flowers.. hiding secret caves and full of hikes.. and then imagine ALL of this completely submerged under water to form the massive Planina disappearing lake in the winter, so huge it is visible from the motorway between Ljubljana and the coast!

This lake can also be described as a Karst field, now Karst is a Slovenian geological term to describe leaky limestone rock areas that create phenomena like disappearing lakes and caves. There is a whole underground Karst Kingdom covering half of Slovenia where water flows from the mountains and rivers into a massive interconnected underground spaghetti waterway that is so complicated it will never be 100% mapped or mastered by man..

When the water table fills, huge lakes appear all over the Karst.. in just a matter of days., when the water table reduces.. these lakes disappear just a fast!

So this is where we get the term disappearing lake from and these lakes can also drain away just as quickly, like magic.. By and large you would expect to see a temporary lake in the winter and then a paradise green meadow in the summer..

The daddy, or as this is mother nature, we should say Momma of them all is the nearby Cerknica disappearing lake, which can fill to about 40 square km and even this wonder of European nature is hardly known outside Slovenia.. but think about it.. if you had an amazing disappearing lake like Planina in your country it would be top of the Green tourism ratings!

There are 2 major reasons why You might be interested in Planina lake, just 20 mins from the Lodge..

1. You can easily find huge clues here to see and understand how a Karst disappearing lake works.. If you know where to look (and we give guests a map and point out where to go), then you can see exactly how this lake functions.. even if you are not lucky enough to be here on the exact days when it is magically filling or draining!

And if you ARE lucky enough to be here when the lake is appearing or disappearing, then bingo.. you have hit the jackpot!

2. Secondly, at Planina, there are so many other little natural wonders either connected to the lake by nature or history.. You could spend all day or half day here easily and Planina is also handily placed on the way from the Lodge to so many other Green wonders.. so we will tell you all about them below.. 

it is amazing how these trees in the lake survive..
it is amazing how these trees in the lake survive..


How does a disappearing lake form?

Water can come from anywhere underground in Slovenia and at the massive Cerknica lake it comes up from enormous sink holes in the field and caves along the side of the lake.

This also happens at Planina and there are also sink holes and caves to discover in the meadow expanse. There is even a big metal grill that you can try to find.. this stops trees and bulky materials getting sucked under the ground when the water disappears!

But Planina makes it even easier for you to see and even follow how so much water reaches this field.. the lake is largely fed by the Unica river which bursts out from the fantastic Planina cave at the very edge of the field and meanders like a wiggly snake, fizzling out in the middle of the meadow.

Even this river is incredibly special.. as it is actually one part of the "River of 7 Names".. a river that starts in Croatia and flows all the way to Ljubljana, but pops under the ground to join the spaghetti water network 7 times and every time it pops back up onto the surfcace to continue the river, it gets a new name! What about that!..

this side road is just about disappeared..
this side road is just about disappeared..


So the Planina lake is mainly formed when this river swells up massively and gushes out of the cave.. there is always usually some water flowing through the cave and there are times when you cannot even hear yourself think as it flows so loudly.. but you can go into the cave yourself a bit to look around and then after follow the flow of the water out into the forest, under the stunning 4 arched bridge and then into the main meadow if you like to get a real connection with the lake and how it forms.

And just one road survives when the lake floods . This is due to a man made clue that you can see even when the lake is empty in the summer! All the other local roads and tracks on the lake are completely submerged in water, but the main road from Planina over the field to the bridge has been built high up a little like a dam, with some big holes in the side so the water gushing from the cave can get through and fill the rest of the lake without covering this road! If you didn't know this, it would be so easy to just drive along the road and not even notice the beauty and significance of it!

If you are lucky enough to be here when the water is rising and turning green fields into a lake, you can see how the water crosses from one side of the road into the main field.

And the main Planina road, which goes higher up along the length of the lake from Planina towards Logatec is another great place to observe the lake when it has formed.. For km after km, the water fills the massive meadow, submerging trees and creating one of Slovenia's biggest lakes in just a few days! 

There are plenty of viewpoints and little parking places along this road to pull over and appreciate the size of the lake for yourself. 

And if you are coming from the bridge towards Planina look carefully how the houses in the town are positioned, higher up in a line along the shore of the lake.. again in the summer you might not notice the importance of this, but in the winter it is clear to see that centuries of local experience with the lake has shown the people where they can build houses and where not.. this is nature's decision, not man's.

Now You see it..

the Planina disappearing lake appears..
the Planina disappearing lake appears..


Now You Don't!!

Planina hill towers over the village.. you could go hiking up there!
Planina hill towers over the village.. you could go hiking up there!


What Adventures can I get up to at Planina Disappearing Lake?

We very often go via Planina to cut out Postojna if we are taking the motorway towards Ljubljana, it only takes 5 minutes more.. but is so much more beautiful and green and very often you will not even get one other car on the same road! We explain more about the route in this article, Fab Cross Country Short Cut to the Lodge.

But the point here is, Planina is so close to the Lodge and very quiet, so it would make a sensational and unforgettable day to come visit here by E Bike instead of a car for example.

The road to Planina is largely an ancient Roman Road that was used in later years by carters.. the Carter's Road.. using horses to transport huge Slovenian oak trees from the forests here all the way to Venice to build the island's foundations.. Yes folks.. Venice was built upon Slovenian wood! The wooden carts came directly though our little village of Landol as this was the best route from Planina to squeeze past Nanos mountain, that massive lump of rock that blocks the way into Italy! How good is that.. and you could bike along this road too!

the Bridge

The main bridge across the river Unica has 4 arches and a tiny hidden car park on the other side of the river, where you could stop and enjoy the river, even swim there on hot days. And of course the Unica river flows from the cave under this bridge and into the massive field, so this is a very good point of access to the rest of the river.

a great spot for a swim on  hot summer day..
a great spot for a swim on hot summer day..


Haasberg Castle 

This is one of the best totally ruined baroque castles in Slovenia and you can find it if you go away from Planina and directly across the bridge and TURN OFF the main road to go straight up the hill a bit. The castle was once a very grand residence, getting pretty much destroyed after WW2, but it is a marvellous starting point to explore the forest and tracks between here and another one of Green Slovenia's wonders of nature, the Rakov Skocjan Stone park..


The Unica river is known among anglers as one of the very best fishing rivers in Europe for colourful rainbow trout! You must buy a permit in the little shop in Planina village for the day and the best fishing is further down from the bridge as the powerful fish swim up river.

Hike to st Lawrence

If you look towards Planina from the lake you will see the high rolling hills above and these stretch all the way towards Nanos mountain behind the Lodge.. the highest peak in between is St Lawrence at 1,019m. Not so high, but it has fantastic views either side of the summit to the Slovenian Julian Alps, Ljubljana and Nanos and it would make a truly wonderful day hiking from the disappearing lake up Planina hill to the pretty church and then all the way to St Lawrence above the tree line walking along the high ridges.

Storks nest

Maybe you have these at home too, but Slovenia is a paradise for gangly storks returning from South Africa to the very same nest each year and there is one huge straw nest in a wonky chimney above one of the houses up by the main road in Planina to find! Locals say that Spring only begins when the storks return and if you are really lucky you might see the chicks sticking their beaks out of the nest at the right time of year!

The Meadow 

Obviously in winter you would need a canoe, but in summer the water quickly disappears and the lushest grass you could hope to find appears, warmed by the Slovenian sunshine.. There is a huge area here to hike around, maybe find some of the sink holes or caves with unique flowers and buttterflies whizzing around.. it really is a green paradise.

Rapunzels Tower

You never saw a tower more likely to be the real Rapunzels tower than "Ravbar tower" which pops its giant coned head out of the forest.. so that is what we call it.. Rapunzels tower!! This huge look out post was used to guard and observe what was going down in the forest neighbourhood, especially to check for smugglers, the most famous of these being Slovenia's own Robin Hood, a real big man by the name of Martin Kirpan, who swung a massive axe over his shoulder and was even known to pick up his horse and carry it through the forest so the emperor's soldiers could not hear him sneak past!

It MUST be only a matter of time before you can actually go up inside the tower for the view, but this place is so Slovenia and so fairy tale that it is magical just to walk around the base of it, high above the river and suck all the green history in.

stunning stone approach to the cave..
stunning stone approach to the cave..


Planina Cave

There is a dinky little car park close to the tower, (look for the brown sign on the hill up out of Planina towards Postojna and turn left), and from here you can walk through a secret gate down a forest path to a man made canal that diverted some of the water to an old mill. The river rages on the other side and a Karst rock cliff towers 50 metres above you as the mouth of Planina cave opens up.

This is one of the most spectacular and unexpected entrances to a cave in Green Slovenia and you can go alone inside a little into the massive cave mouth until a metal gate further along the dark rock walkway above the river. Depending on the time of year, you might be lucky enough to even see a mysterious cloud floating inside the cave!

And another amazing green secret can be found on the official tour inside this cave.. This very special water gushing out is not only the water that will make a disappearing lake.. or that will create another of the River of 7 names.. oh no, it is also the water that is formed deep inside this fantastic cave when TWO different rivers crash into each other, the other river comes from the nearby Postojna cave and Planina is the only cave in Europe where you can see this feat of nature!

If you also consider this cave has over 1,000 baby dragons hidden away inside then it is a very special secret cave indeed and you can visit it in the summer once a day at 5pm.. you could very possibly the ONLY people on the tour.. so really.. your choice.. a train, half the world and a hamburger or the magic of Planina cave!! 

Our advice is to see them both of course and as many other show caves here as possible.. Green Slovenia's caves are all so completely different and we are blessed with the best selection of show caves in Europe. 

Our guests often arrive at the Lodge having heard of just one particular cave upon arriving in the Green Karst.. afterall Slovenia is so small isn't it, so how could it be packed with more fantastic caves than any other country in Europe.. well it is!

We regularly nudge our guests to fit in a visit to Planina cave and without exception they are blown away by the beauty and solitude of it all.. we will always remember a lovely lady from Texas who said her time in Planina and Rakov Skocjan was the highlight of her European trip.. it is just soooo different and soooo green.. last year we had a German couple who did the new kayaking trip up the river into Planina cave and if you want more of a rough & ready unique adventure, then this is the one for you. 

So this cave is the mouth that feeds the lake and now you know what a disappearing lake is and where to find it and what you can do there.. we sincerely hope a whole new day of Slovenian Green adventures has now opened up for you!

Maybe you have seen our second YOUTUBE video, maybe not, but we got some amazing footage of the Planina lake after heavy unseasonal rain just sightly filled it up with little ponds.. it looks like a massive golf course where the bunkers are small lakes and you can find the video here at Lipizzaner Lodge.. Discovering Green Slovenia.


Address: Landol 17, Postojna 6230, Slovenia

Phone: +386 5620 3443
Mobile: +386 40 47 0239 or +386 40 37 8037