The top of the hill was originally used as a quarry in the Middle Ages. The stones were used for the collegiate church and the Old Castle in Stuttgart, as well as the Ulm Minster, among other things. You can still see the crater of the former quarry today - it now houses a playground.
Originally called Reinburghügel and was then named in 1889 after the Württemberg King Karl. At the top was since the Middle Ages a quarry in which there is now a …