Natural wonder Europe
Apennines
The Apennines are mountains in Italy. Some of their rocks were made in old seas. A rare kind of brown bear lives there.
The Apennines are a chain of mountains in Italy. Some, like the Majella, are made of carbonate rock that formed in ancient seas and was later folded as plates of Earth's crust moved. In the central Apennines lives the Marsican brown bear, one of Europe's rarest mammals.
The Apennines' evolution is tied to the rollback of a subducting slab that opened the Tyrrhenian Sea from about 10 million years ago. Central ranges such as the Majella expose Mesozoic-Tertiary marine carbonates folded into anticlines, and the central Apennines hold the endemic Marsican brown bear, estimated in a 2025 survey at about 81 animals.
Photo: kallerna, CC BY-SA 4.0, via Wikimedia Commons
Discover the Apennines
The Apennines are mountains in Italy.
This photo was taken from high in the sky. Snow covers many of the mountains, and white clouds float below.
The Apennines are a chain of mountains in Italy. This photo looks across the central Apennines from the air, over the area of the Abruzzo, Lazio and Molise National Park, on 5 April 2026.
Row after row of ridges stretch toward the horizon. The higher ones are white with spring snow, the lower slopes are brown and green, and small clouds drift over the valleys, casting dark shadows.
The hero photo, taken from the air by the Commons user kallerna on 5 April 2026, looks over the area of Abruzzo, Lazio and Molise National Park in central Italy. Its Commons description names the Maiella and the snow-covered Monti Marsicani summits, Monte Schiena di Cavallo, Monte Palombo, the Vallelonga valley with its side valley Val Cervara, and Serra Lunga in the foreground.
Snow lies on the higher ridges, the lower slopes are bare or wooded, and scattered cumulus clouds throw shadows across the valleys.
- Photo area
- Abruzzo, Lazio and Molise National Park, central Italy (Commons)
- Rocks of the Majella
- Lower Cretaceous to Tertiary marine carbonates (ISPRA)
- Tyrrhenian Sea rifting began
- about 10 million years ago (Rosenbaum and Lister, 2004)
- Marsican brown bears
- about 81 (range 73 to 88), 2025 survey, reported 2026
Sea rocks folded into mountains
Long ago, a sea covered this place. Layers of rock formed on the sea floor.
Later, the rock was pushed and folded up into mountains.
Many Apennine rocks began on the floor of ancient seas. The Majella, one of the central Apennine mountains, is made of carbonate rocks that formed from the Early Cretaceous into the Tertiary, both in deep water and in shallow seas. Later, these layers were bent into a big fold called an anticline.
Scientists link the Apennines to one plate of Earth's crust sinking under another. As the sinking plate rolled back, the crust behind it stretched, and the Tyrrhenian Sea began to open about 10 million years ago.
ISPRA's 1:25,000 geological map describes the Majella as an arc-shaped anticline, trending northwest-southeast in the north and north-northeast to south-southwest in the south, built of Mesozoic-Tertiary carbonates (Lower Cretaceous to Tertiary basinal and shallow-marine facies) overlain by Messinian evaporites, hemipelagic marls and lower Pliocene flysch, and partly covered by a thrust nappe.
Rosenbaum and Lister (Tectonics, 2004) reconstruct the opening of the Tyrrhenian Sea from about 10 Ma in two episodes of back-arc extension induced by the rollback of a west-dipping subducting slab. In the central Apennines, their reconstruction indicates, the latest Messinian (6 to 5 Ma) arrival of a carbonate platform at the subduction zone impeded subduction and initiated a slab tear and major strike-slip faults.
The Marsican brown bear
A rare brown bear lives in these mountains and nowhere else.
Scientists collect bits of bear hair to count the bears.
The Marsican brown bear is a kind of brown bear found only in the central Apennines. Italy's environmental research institute, ISPRA, calls it one of Europe's rarest mammals.
In summer 2025, scientists set up more than four hundred scent lures near rubbing posts and berry patches in the Abruzzo, Lazio and Molise National Park and collected 854 hair samples. In July 2026, the Italian news agency 9Colonne reported that the survey counted about 81 bears across more than 6,000 square kilometers.
The Marsican brown bear (Ursus arctos marsicanus) is a subspecies endemic to the central Apennines, across Abruzzo, Lazio and Molise; ISPRA's DigitAP project page describes a very small population of about 50 individuals at severe risk of extinction and aims to produce the first range-wide estimates of its size and distribution. ISPRA reported the first phase completed: 854 hair samples from more than four hundred scent-trap installations in the national park, for genetic analysis.
According to 9Colonne (20 July 2026), the results presented to Italy's environment ministry gave 81 bears (uncertainty range 73 to 88) over more than 6,000 km², with the historic core stable and expansion into new areas still fragile.
Visiting safely
Bears live in these mountains. Never go near a bear.
Stay on the path with a grown-up.
The central Apennines are home to wild brown bears, which ISPRA notes feed in berry patches. PlayOwl's advice: stay on marked trails, never approach or feed a bear, and keep food packed away.
PlayOwl's advice also: check mountain conditions before setting out, because this April photo shows snow still lying on the high ridges.
ISPRA's bear monitoring uses non-invasive genetic sampling: hair left at scent traps and rubbing posts, so the bears are not caught. PlayOwl's own advice for visitors: keep to marked trails, never approach or feed bears, store food securely, and keep dogs on a leash.
The hero photo shows snow on the higher ridges in early April, so hikers should expect snow at height well into spring and check mountain conditions before setting out.
Amazing facts
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Scientists count the rare bears using bits of their hair.
To count Marsican brown bears without catching them, scientists collect hair the bears leave on scented rubbing posts.
ISPRA's 2025 campaign gathered 854 hair samples from more than 400 scent-trap installations for genetic analysis.
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A geologist called one Apennine mountain a training ship for geologists.
The geologist Paolo Scandone called the Majella a real 'training ship for geologists' because its rocks are so well exposed.
ISPRA quotes Paolo Scandone calling the Majella a 'training ship for geologists', thanks to its excellent carbonate outcrops.
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The Marsican brown bear lives only in the central Apennines.
The Marsican brown bear is found nowhere else on Earth except the central Apennines of Italy.
Ursus arctos marsicanus is endemic to the central Apennines (Abruzzo, Lazio and Molise), per ISPRA's DigitAP project.
Words to know
- carbonate rock
- rock such as limestone, made mostly of carbonate minerals
- fold
- a bend in layers of rock caused by squeezing
- anticline
- a fold in rock layers shaped like an arch
- subduction
- when one plate of Earth's crust sinks under another
- endemic
- living naturally in only one place
- genetic survey
- counting animals by studying the DNA in things they leave behind, like hair
Discovery challenge
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In which country are the Apennines?
In which country are the Apennine mountains?
The Apennines run through which country?
- Italy
- Norway
- Peru
Show the answer
Italy
Italy.
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Where did the Majella's rocks first form?
Where did the carbonate rocks of the Majella form?
In what setting were the Majella's Lower Cretaceous to Tertiary carbonates deposited?
- In ancient seas
- Inside volcanoes
- In a desert of sand dunes
Show the answer
In ancient seas
In the sea, long ago.
In ancient seas, both deep and shallow.
Basinal and shallow-marine settings.
-
Which sea began to open as the mountains formed?
Which sea began to open about 10 million years ago, according to Rosenbaum and Lister?
Which back-arc basin opened from about 10 Ma through slab rollback?
- The Tyrrhenian Sea
- The Baltic Sea
- The Red Sea
Show the answer
The Tyrrhenian Sea
The Tyrrhenian Sea.
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Which rare animal lives in the central Apennines?
Which rare bear lives only in the central Apennines?
Which subspecies is endemic to the central Apennines?
- The Marsican brown bear
- The polar bear
- The giant panda
Show the answer
The Marsican brown bear
The Marsican brown bear.
The Marsican brown bear.
Ursus arctos marsicanus.
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How do scientists count the bears?
What did scientists collect in 2025 to count the Marsican brown bears?
What material did ISPRA's 2025 campaign gather for genetic analysis?
- Bear hair
- Bear footprints in snow
- Photos from space
Show the answer
Bear hair
They collect bits of bear hair.
Hair samples, 854 of them.
854 hair samples from scent traps.
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For parents & teachers
What children will learn
- Locate the Apennines in Italy.
- Explain how sea-floor rock can end up in mountains.
- Describe how scientists count rare animals without catching them.
- Know how to behave safely in bear country.
Recommended ages: 3 to 17 · About 15 minutes
Talk about it
- How could rock that formed in the sea end up on a mountaintop?
- Why might scientists count bears from hair instead of catching them?
- What could help a small bear population spread into new areas safely?
Try at home or in class
- Stack a few colored sheets of play dough and push the ends together with a grown-up: watch the layers bend into an arch, like an anticline.
- Drop a little vinegar on a piece of chalk or limestone with a grown-up and watch it fizz: limestone and chalk are carbonate rocks.
Key vocabulary: carbonate rock, fold, anticline, subduction, endemic, genetic survey
Where these facts come from
- Wikidata , Wikimedia Foundation (CC0 1.0)
- The geological map of the Majella Mountain , ISPRA, Italian Institute for Environmental Protection and Research
- Neogene and Quaternary rollback evolution of the Tyrrhenian Sea, the Apennines, and the Sicilian Maghrebides (Rosenbaum and Lister, Tectonics 23, 2004) , The Australian National University research portal (abstract)
- The first phase of genetic monitoring of the Marsican brown bear has been completed , ISPRA, Italian Institute for Environmental Protection and Research
- Non-invasive genetic sampling of Marsican brown bears for biomolecular analyses and population size estimation (DigitAP project) , ISPRA National Biodiversity Network
- Wildlife: census counts 81 endangered Marsican brown bears (20 July 2026) , 9Colonne (Italian news agency)
- File:Abruzzo, Lazio and Molise National Park aerial.jpg , Wikimedia Commons
- Wikimedia Commons , Wikimedia Foundation (Per file (public domain, CC0, CC BY or CC BY-SA); see each media record)
Checked, not yet human-reviewed. Last updated November 1, 2026. Spotted a mistake? Tell us.