Stags in season
There’s nothing like experiencing the roaring and strutting of stags in season. Denmark has many places where you can get close to the action in late summer and autumn, as stags put on impressive displays to attract females and defend their territory. The rutting season lasts about a month. The deer in Denmark’s deer parks have become accustomed to a quiet human presence, so you really can witness this amazing annual ritual from up close. You can see red and roe deer at Haderslev Jægersborg Deer Park, 15km north of Copenhagen and you can also catch the action with deer at both Thy Oxbøl and Slotved Forest in Jutland.
The Black Sun
At Tøndermarsken in the Wadden Sea National Park, South Jutland, you can see the unbelievable natural phenomenon known as the Black Sun. Occurring in spring and autumn, the Black Sun occurs when thousands of starlings gather at dusk, drawing amazing dark patterns on the sky. This stunning sight draws thousands of onlookers each season and is well worth travelling to the park for. You should plan a few days out on the flat marshes to truly soak up the Black Sun. Though Tøndermarsken is the best place to witness this, you can also catch it around Ribe, Tipperne at Ringkøbing Fjord and on Rømø island.
Seal and porpoise watching
There are many seal colonies on rocks and small islands around the coast of Denmark, some of which you can visit by boat. You’ll see seals and porpoises popping up all around the Danish coastline. The most common seal in Denmark is the spotted seal, but if you’re lucky, you may spot the much rarer grey seal. Seals are inquisitive but shy animals. Sometimes access to seal colonies is restricted, such as at the Rødsand Seal Reserve on Falster island, the most important breeding ground for spotted seals in the whole Baltic Sea. The area is closed to visitors in the breeding season from March to the end of September. Denmark has sealariums in Esbjerg , Hirtshals , Kerteminde  and Grenaa , where you can get really close to these elegant, underwater creatures. Porpoises are small whales with distinctive dorsal fins. You can often spot them in the waters of the Great and Little Belts, the Skagerrak, the Kattegat and the North Sea. On the island of Rømø, you can take a seal and porpoise safari. Ask for details at the local tourist office.
Some people have a real eye for amber, Nordic gold, which you can find all along Denmark’s coastline. Chances of finding these little gems hidden on the beach are best where it is most windy and where the surf is biggest, so the West Coast of Jutland  and the Kattegat coast are particularly good. Amber is small lumps of ancient resin that wash up from the sea floor and can sometimes be as old as 50 million years. In some, ancient insects have been caught inside as it hardened. Amber has always been treasured and used for jewellery and ornaments. Amber can be tricky to spot because it is not only yellow in colour, it can also be white, black or reddish and you can easily mistake it for stones. Here are some simple tricks for checking your find is the real deal:
Knock it carefully against your teeth. If it feels soft and doesn't clink too much, it’s probably amber.
Rub it against your clothes and then hold it up to a strand of hair. If the hair is attracted to it, it’s amber.
Put it in a glass of water with two spoons of salt and stir. If’s amber, it will float to the surface.
If you squeeze or rub it and hold it against your cheek, amber will feel warm and soft.
There are several amber museums around Denmark, displaying some of the most impressive pieces of amber and ancient jewellery and ornaments. Find the nearest one at your local tourist office.
If you are brave enough to head underground, Denmark has some incredible abandoned mine networks and natural caves which are open to the public. In many of these, you’ll have to share the eerie darkness with colonies of bats, sometimes numbering tens of thousands! Jutland has three well-known abandoned mines – Mønsted Limestone Quarries , Daugbjerg Limestone Mines  and Thingbæk Limestone Mines . All three are now open to the public with museums and subterranean adventures. Together, they offer hundreds of kilometres of underground world to explore and you can really get a sense of what life was like for the miners who used to work down there. The island of Bornholm is covered with open caverns known as Ovens. Some of them are only accessible by sightseeing boat, others you can reach on foot. You can find out more about how these dramatic formations were created at the Naturbornholm Centre  in Aakirkeby.
If you’re lucky enough, you can find fossils all over Denmark. Fur island in Limfjord and the southern coast, particularly around the Møn and Stevn cliffs, are fantastic fossil areas. You can find prehistoric treasures scattered around, without needing any equipment. Typical fossils in Denmark include sea urchins, belemnite fossils and crab shells. You can keep the fossils you find, providing they aren’t extremely rare, in which case you’ll need to hand them over to the nearest geological museum for everyone to marvel at. You can find your nearest museum at the local tourist office. Experience the birth of Denmark at the exciting GeoCenter Møns Klint . Not only does the centre have fascinating exhibitions on the geological history of Denmark for you to enjoy, but they also organise fossil hunting and other outdoor expeditions into the local area.
GPS Treasure hunts
Geocaching is an outdoor, interactive treasure hunt where you use a GPS to search for a hidden treasure. Many people around the world take part in this sport and there are hundreds of treasures hidden around Denmark. Treasures tend to be small pots with a log book and small gifts in. If you succeed in finding the treasure, you can take some of the treasure and log your find in the log book. You can then visit the Geocaching website  to register your find and to see other treasures waiting to be found.
Dinner in the forest
There are many areas across Denmark designated as places where you can set up campfires. National parks and public nature areas such as forests may even have covered areas with benches and other facilities. It’s important that you only use designated areas to cook your wild dinner in the forest, so check where you can find campfire areas with your local tourist office.
Depending on the season, the Danish countryside is full of wild berries, nuts, mushrooms and other edible plants. You are welcome to gather these delicious wild treats in public areas. As a general rule, you should leave some for others, so try not to take more than a carrier bag’s worth from any one place.
Sleeping in the wild
If official campsites are not your thing and you crave the serenity of a night camping in the wild, Denmark is the country for you. With over 1,000 areas for wild camping, there are a multitude of natural camping experiences waiting for you. No caravans or motorised vehicles are allowed in these places. They are pure, unspoilt spots where you must leave nothing but your own footprints behind.
Wild camping sites are often equipped with running water and toilet and around a third have shelters you can sleep in. You may only sleep a maximum of two nights at each location.
The Danish Nature Agency gives the following guidelines for wild camping .
They also have a map of all wild camping spots in Denmark. This function is in Danish but if you click “Overnatning” on the left-hand menu, all the wild camping spots (primitive overnatningspladser) will be shown on the map of Denmark.
There are eight special areas in Danish forests where you can let loose and mountain bike off the normal marked paths out into the forest. They are:
- Bidstrup Forest in North Zealand (9.5km)
- Blåbjerg Klitplantage south of Ringkøbing Fjord (7.3km)
- Bordrup plantation at Båvands Huk (6.8 and 8km)
- Klosterheden northwest of Holstebro (50km)
- Hare woods northwest of Copenhagen (26km)
- Rold Skov in Jutland (23km)
- The forest just north of Copenhagen (10km)
- Aabenraa Forests in South Jutland (8.4km)
If you don’t have your own mountain bike with you, you can hire one in most bike shops in Denmark. You should expect to pay around 150 and 200kr for a day’s hire.
Read more about Natural adventures in Denmark .
Read more about Cycling in Denmark. 
Read more about Family holidays in Denmark .