Mønsted Limestone quarries to the west of Viborg is the world's largest limestone quarry. Limestone was quarried here for several hundreds of years until 1953. There is approximately 60 kilometres of underground passages on several levels and some of them are enormous with tall, beautiful, almost cathedral-like rooms, others are so small that grown-ups must bend down to get through. The quarries are used for concerts from time to time and during the winter months, approx. 5,000 bats hibernate there.

It would be wise to allot a couple of hours for the visit, so you can see everything – the multi media show which explains about the limestone and the quarries in sound and pictures as well as the light sea by the big lake.

Daugbjerg Limestone mines, also situated to the west of Viborg, is only 3 kilometres from Mønsted Limestone quarries. You navigate the long mine passages carrying a candle in your hands, some places they are up to 60 meters deep. Underway, you get a great impression of the life led by the miners and you will see some of the approx. 12,000 bats hibernating here, see fossils and much more. The kids can participate in a treasure hunt with exciting prizes and the museum has fossils and tools on display.

Thingbæk Limestone mines located to the north of Rold Forest is home to one of Denmark's most distinctive museums. The mines were owned by the sculpturer Anders Bundgård, who had to realize that mining was not particularly profitable. Therefore, in 1936, he converted the mines into a sculpture museum the majority of which are his own works. Therefore, you can among other things see the plaster model of the Cimbrer Bull in Aalborg and the Gefion Fountain in Copenhagen. There is a variety of exhibitions and concerts in the mines for the benefit of visitors and the many hibernating bats alike.

The rocky island of Bornholm situated in the Baltic Sea has several exciting caves and caverns – locally referred to as ovens. The largest oven is the 70 meter long Våde Ovn (Wet Oven), situated by Hammershus at the northern point of the island. You have to travel by the sightseeing boat (www.hammerhavnensbaadfart.dk) from Allinge to get there, and it is a beautiful trip along the steep, rocky coast of Hammeren (The Hammer). Other, but smaller, ovens are found by the Helligdomsklipper (the Sanctuary Cliffs) by Rø; moreover, there is Sorte Ovn (Black Oven) and Sorte Gryde (Black Pot). Ask the local tourist offices where and how you find these and other ovens.

At the experience centre Naturbornholm in Aakirkeby, you get plenty of exciting knowledge and great stories about Bornholm's nature.

Both in Mønsted and Daugbjerg Limestone quarries, a large amount of cheese is stored, because thanks to the stable temperature and high humidity, the conditions are perfect. In Daubjerg, they also store sausages and wines. Everything can be purchased from the mine's kiosk, so you can actually get a very nice and simple lunch, if you bring along some bread.

The three limestone mines in the middle of Jutland are usually open from April to October. Moreover, they can be open in connection with special arrangements during the months of winter. Have a look at the mines' homepage.

The ovens of Bornholm are all situated in open nature, so it is the weather and wind that decides when they are accessible.

There are also caverns in Denmark that you should definitely not enter. These are the many small caves which you see in slopes and cliffs along the coast. They look exciting and tempting, but they can be potentially fatal because there is a high risk of collapses.