In a tropical ocean 430 million years ago, there were coral reefs.

- Gotland's reef limestone is one of the world's best-preserved with world-class fossils.

Gotland is perhaps the finest place in the whole world when it comes to the Silurian period, says geologist Sara Eliason.

Over the course of millions of years, the limestone skeleton of the coral reef became the hard reef limestone, of which the Södra Hällarna where we stand, is a good example.

It is within walking distance of Visby and is one of Gotland's later reserves.

See in the video how just above the popular swimming spot there are several football-sized holes for fossils.

At the edge of the beach, only the pit after the "cat's skull" remains.

Photo: Lena Liljeborg/SVT

"Make all of Gotland a geopark"

In order to protect the fossil, Sara Eliason wants the history of the bedrock and the fossil to become the main thing in a world heritage site and believes that it should include all of Gotland.

- The whole of Gotland reflects this geological history in such a fantastic way, but in different ways around the island.

So it's hard to pick just one place.

Knocked away fossils in the middle of the beach

This summer, "cat skulls" have disappeared at the popular bathing spot in Sigvaldeträsk.

In the middle of the small strip where everyone walks and also a little bit above the lake, there are several holes after knocked away fossils.

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In the middle of the beach where everyone steps, there is now only a pit after the "cat's skull".

Just above there are several football-sized holes after fossils knocked away.

See this in the video.

Photo: Lena Liljeborg/SVT