It is actually two castles in one. The first is the sorrowful dark-stone towers of the old Wenden castle. Founded by Livonian knights in 1214, it was sacked by Russian tsar Ivan the Terrible in 1577, but only after its 300 defenders blew themselves up with gunpowder. The other is the more cheerful castle-like 18th-century manor house once inhabited by the dynasty of German counts von Sievers. It houses a museum that features original fin de siècle interiors.
After visiting the old and the new castles, take a walk through the landscaped castle park with a pond inhabited by the cutest of paddle steamers that takes people around for €2.20. Just as cute is the hilltop Russian Orthodox Church of Transfiguration, which the von Sievers built at their family cemetery (like many Germans on Russian service they converted to Orthodoxy).