The most powerful tower of the Freinsheim town fortifications is the "Herzogturm" (Duke's Tower). It was built on a square ground plan of 7 x 7 m, closed all around from the beginning. The lower storeys had neither doors nor windows, which suggests an earlier use as a dungeon. It is very likely that its name comes from the Dukes of Zweibrücken, who had estates in the vicinity. Today, after extensive renovation work, the tower houses 2 hotel rooms on 4 levels, which can be booked through the "Landhotel Altes Wasserwerk".