In historical times, high ridges and spurs were used as sites for fortified castles (Burgen). In the Harz these include Falkenstein Castle, where Eike von Repkow probably drew up the Sachsenspiegel, the most important legal code of the German Middle Ages, Hohnstein Castle near Neustadt/Harz, Lauenburg Castle near Stecklenberg, Plessenburg and Stecklenburg, as well as the ruined castles of Harzburg, Anhalt, Königsburg, Scharzfels.