The castle tower of Mulken or Templar tower is a 13th-century keep in Mulken. The fortified tower is located on a small artificial hill at De Locht. Of the fortified tower, which was part of the castle of Mulken, only the outer walls are still standing. The roof and the interior layout have disappeared. The whole has an octagonal floor plan with a diameter of 4.6 meters. The walls are approximately 1.85 meters thick. The adjacent estate, consisting of a house and a farm, was rebuilt in the 17th century and renovated in the middle of the 19th century. The fiefdom of Mulken depended on the church of Liège and was already inhabited by the knights of Mulken in the 12th century. On April 19, 1598, Jan van Herckenrode bought the fiefdom, which was in a dilapidated state at the time. In 1628 Jan van Herckenrode had the estate thoroughly restored, as is evident from the text flanking the family crest above the doorway of the castle tower; JOANNES HERCKENROYE ME FIERI CURAVIT ANNO 1628 (Translation: Jan van Herckenrode ensured that I was made in the year 1628) and VENI, VIDI, FLEVI (Translation: I came, I saw and I wept).