Halvardsborg was an ancient stronghold in Arboga. It was built probably between 400-550 AD. It consisted of 520m long and even 3m high stone wall. There are some remains of the wall today.
Fiskebäckskil Church replaced in 1772 the earlier wooden church from 1500s. The beautiful paintings in ceilings were made in 1783 by Joachim Gotthard Reimers. The altar dates from 1665.