In the largest of the six Valle nature reserves lie the ruins of the old Höjentorp castle. Thought to have been granted to the Skara bishop in 1284, it was returned to the crown during the reformation forced through by King Gustav Vasa.

In the mid-1600s Queen Kristina gave it as a morning gift to Maria Eufrosyne, wife of Count Magnus Gabriel de la Gardie. The castle burnt down in 1722 during a visit by Queen Ulrika Eleonora, who watched the conflagration from a nearby hill, now called Drottningkullen or Queen's Hill. All that remains are cellar ruins, but the site bears witness to the area's medieval importance, a time when Skara too was at its height. The now wild gardens are home to handsome ash trees and lindens, while the slope towards the Trädgårdsjö lake exudes rare flower fragrances. Carl von Linné's comment as he travelled through in 1746 that "Höjentorp commanded the most  pleasant site and owned the most complimentary location". Cross to the northern shore of the idyllic Trädgårdsjö lake on Kungsbron bridge where the ruins lie but a stone's throw from the old Höjentorp country estate. This is where Jonas Alströmer of potato fame ran an agricultural school during the 1700s.