The "Dicke Stein" is one of the largest boulders of the [Münsterland] es and a block of sediments from Neokom sandstone, which the glaciers from Osning near [Bielefeld], today's [Teutoburger Wald], transported to Ahl some 150,000 to 250,000 years ago , With dimensions of 5.2 x 2.8 x 2.6 meters, the stone has an estimated weight of about 75 to 90 tons.
The "Dicke Stein" was discovered in 1911 on the property of Anton Rötering. After being uncovered from 16 to 19 January, it was raised in 1913 by means of two hydraulic jacking equipment from the Westphalia coal mine and was to be brought to the city park. Only later did it become apparent that the Dolberger Straße bridge over the Werse could not bear the weight. In 1916 it was decided to place the stone at its present location. The lifting action took four full days and another six days were needed for transport. The elaborate work required 10 men. The cost of this