Denmark’s fossil cliffs at Hanklit on the island of Mors and Knudeklint on Fur have been added to the UNESCO World Heritage List. The World Heritage Committee approved the designation on Saturday, 25 July, during its annual meeting in Busan, South Korea, recognising the cliffs’ exceptional record of life and climate change around 56 million years ago.
The new natural property is officially named “The Bony Fish Fossils of the Western Limfjord – Evolution and Climate Adaptation in the Earliest Eocene.” It consists of two coastal sites in the western Limfjord: Hanklit, which covers 3.79 hectares, and Knudeklint, which covers 3.19 hectares.
Danish fossil cliffs preserve an exceptional record of evolution
According to UNESCO, the cliffs contain some of the world’s best-preserved fossils of bony fish. The site provides important evidence of how modern fish groups evolved and diversified after the mass extinction that ended the Cretaceous period.
The deposits preserve between 25 and 29 fish orders and more than 80 fish species. Fossils of sea turtles, birds, insects, plants and microorganisms have also been found in the sediment.
Many specimens retain unusually fine anatomical details because they settled on a seabed with very little oxygen. The lack of bottom-dwelling organisms meant that remains were often left undisturbed before being covered by new layers of sediment.
The cliffs therefore offer a detailed view of marine and terrestrial ecosystems during the earliest Eocene, when the planet experienced rapid environmental change.
A geological archive of ancient climate change
Hanklit and Knudeklint contain layers formed approximately 55 to 56 million years ago, including sediments deposited during the Paleocene-Eocene Thermal Maximum. During this period, global temperatures rose sharply following the release of large quantities of carbon into the atmosphere and oceans.
The fossil record shows how animal and plant communities responded to this warming and to the cooling period that followed. UNESCO considers the area particularly valuable because it combines well-preserved fossils with an almost continuous geological sequence.
The cliffs are composed partly of moler, a sediment rich in microscopic diatoms that is found only in the western Limfjord area. The deposits are interspersed with more than 200 layers of volcanic ash linked to the opening of the North Atlantic.
These ash layers allow scientists to date different parts of the sequence with considerable precision. The visible folds and displacements in the cliffs were formed much later, when Scandinavian ice sheets pushed and reshaped the sediments during the last glacial period, as described in the site documentation published by the UNESCO World Heritage Centre.
The UNESCO decision was taken in South Korea
The designation was approved during the World Heritage Committee’s conference in Busan. Representatives of the committee’s 21 member states examined around 30 nominated cultural and natural properties during the session.
A Danish delegation attended the meeting, where the two fossil cliffs were formally inscribed following a presentation of the nomination.
Minister for Culture (Kulturministeren) Zenia Stampe said the site provided a rare view of the planet’s distant past and expressed hope that the recognition would encourage more residents and international visitors to explore the Limfjord area.
“It is very fascinating. I hope that more Danes and tourists will spend a long weekend or a holiday experiencing the moler cliffs,” she said in a statement reported by TV 2 Denmark.
Denmark now has ten World Heritage properties
The inscription brings the number of UNESCO World Heritage properties located in Denmark itself to ten. Across the wider Danish Realm (Rigsfællesskabet), including Greenland, the total has risen to 13.
The existing properties include Roskilde Cathedral, Kronborg Castle, the Jelling monuments, the Viking-Age ring fortresses and the natural landscapes of Stevns Klint and Møns Klint. Greenland’s listed sites include Ilulissat Icefjord and the Inuit hunting landscape of Aasivissuit-Nipisat.
The western Limfjord cliffs were added to Denmark’s tentative UNESCO list in 2023. Their nomination followed more than a decade of cooperation involving Morsø Municipality, Skive Municipality, local museums, researchers and state heritage authorities, according to the UNESCO World Heritage Centre.
World Heritage status also brings new responsibilities
The UNESCO designation is expected to increase international attention and tourism in Mors and Fur. Local authorities will also be required to protect the geological formations and manage visitor pressure without damaging the exposed sediments.
Both cliffs already have national and municipal protections. Hanklit has been protected since 1937 and Knudeklint since 1973. Removing fossils from the nominated coastal areas is prohibited, although amateur fossil hunting remains possible in some former moler quarries elsewhere on the islands.
The inscription gives the western Limfjord a new role in international research on evolution and ancient climate change. It also strengthens Denmark’s growing group of UNESCO-listed geological landscapes, following the inclusion of Møns Klint in 2025.
