Billnäs ironworks was founded in 1641 by Carl Billsten. It faced many difficulties during 17th and 18th century. Local peasants destroyed the ironworks already in 1659 because of too heavy taxation. During the Great Wrath Russians occupied and destroyed it again in the 18th century.
Billnäs Ironworks moved to Hisinger family's possession in 1723. Bar hammer workshops with forges and waterwheels, and coal rooms were built to both sides of the rapids in Billnäs Ironworks. Johan Hisinger was especially active in building and developing the Ironworks’ operations. Billnäs manufactured many kind of forge products until 1920, when it was incorporated into Fiskars Corporation (the another ironworks site nearby).
An industrial business ended in Billnäs in the end of the 20th century. Today it’s moved to the use of service industry. Various public events, concerts and exhibitions among others, are organized in the Billnäs Ironworks. In the long run, hotel- and restaurant operations are planned to the area as well as a full renovation of the valuable real estates. The ironworks area is today a well-preserved national heritage. The most valuable building is the great forge from the 17th century.
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.