Heldenfingen Cliff, Natural monument in Gerstetten, Germany.

The Heldenfingen Cliff lies at the eastern edge of Heldenfingen, a district of Gerstetten. In the white Jurassic rock, the long impact of waves of the Tertiary Molasse Sea carved a typical notch, the Hohlkehle, and the rock above and below it is covered with holes bored by pholad mussels and boring sponges. The sloping rocky sea floor in front of the cliff, exposed only in 1936, carries the same borings.

The cliff was part of the rocky coast of the Tertiary Upper Marine Molasse sea about 15 million years ago. Wave action cut a hollow notch into the White Jurassic limestone, and boring mussels (Pholades) and boring sponges drilled the rock above, below and on the sloping sea floor in front of it. That sea-floor section was only uncovered in 1936. The site was designated a natural monument by the Heidenheim district authority on 10 November 2005.

The Reef Museum in town displays fossils and materials explaining the ancient underwater world that once existed here. You can see what kinds of creatures lived in these waters millions of years ago.

A circular walking and cycling path called the Ancient Sea Trail begins at the cliff and extends about 14 kilometers. The route works well for both hikers and cyclists exploring the surrounding area.

A geological educational playground sits directly at the cliff and offers learning activities for visitors of all ages. The site blends recreation with hands-on science education right at this ancient shoreline.