The ruin of Caldiff or Kaldiff Castle rises on a Dolomite rock in Mazzon, a component locality of Egna on the Wine Road.
It is presumed that Caldiff Castle - just as Enna Castle near Montagna - dates back to the 12th century and the Lords of Enn which had jurisdiction over the area of Egna back then. They had the castle rebuilt in the 15th century, some decades before they assigned it to the Nobles of Payr von Altenburg in 1524 which called themselves Payr von Kaldiff from then on. The family had the building enlarged to a residential complex. At the end of the 18th century, a fire destroyed Caldiff Castle. In 1870 the donjon collapsed, and there is hardly anything left of the curtain wall.
Parts of the north, west and east walls, remains of the frescoes from around 1300 and the heraldic painting on the gate building, as well as the dovetail battlements are still preserved. According to a legend, several treasures are buried here which are guarded by two dogs with flashing eyes. The ruin was carefully consolidated and made accessible to the public: The old castle path was lined with dry stone walls and takes visitors to Caldiff Castle. A round hike starts in Egna and leads in three hours to the mighty castle ruin, the nearby Gleno Waterfall and back to the village again.