Holtwicker Ei, Glacial erratic in Rosendahl, Germany.

The Holtwicker Ei is an egg-shaped granite erratic that protrudes about two metres from the ground at the northern exit of Holtwick, near the B 474. It stands in a small green area at the centre of a square enclosed by a low wall. Its visible weight is estimated at around 30 tons, and roughly twice its height lies buried.

This boulder was carried to its location by glacial forces during the Saale ice age around 200,000 years ago, originating from the Värmland region of Sweden. This ice-age movement shaped the entire landscape of northern Germany, leaving behind thousands of similar granite blocks across the region.

Local narratives tell of the devil's failed attempt to destroy the Holtwick church by throwing this boulder, which landed in its present position.

The boulder is located in a protected area with information signs and is freely accessible year-round. Visitors should note that the site is flat with good walkways, but dressing appropriately for the season is wise since exposure to wind and weather is common.

The name Holtwicker Ei means "Holtwick Egg", and a local legend explains the village name itself: the devil, enraged by church building in Coesfeld and Billerbeck, carried a heavy stone, cried "Holt wiek oder ick smiet!" (Low German for "Get out of the way or I'll throw!") and dropped it here.