Aiello Calabro Castle was probably buillt in the Byzantine period in the 9th century against Arabian raids. It was besieged four months by Norman count Robert Guiscard in 1065. He lost two of his nephews in the siege.
The current ruins date mainly from the 15th century. In the 16th century it was one of the most powerful castles in southern Italy. Aiello Calabro castle was destroyed by earthquakes of 1638, 1783 and 1905. Today part of curtain walls and towers remain.
Frösöstenen is the northern-most raised runestone in the world and Jämtland's only runestone. It originally stood at the tip of ferry terminal on the sound between the island of Frösön and Östersund. The stone dates to between 1030 and 1050. It has now been relocated to the lawn in front of the local county seat due to the construction of a new bridge, between 1969 and 1971, on the original site.
Frösö runestone inscription means: Austmaðr, Guðfastr's son, had this stone raised and this bridge built and Christianized Jämtland. Ásbjörn built the bridge. Trjónn and Steinn carved these runes.