The Valley of Kópavogsdalur is an outdoor and recreational area for the residents of Kópavogur. There is a small stream leading through the town which ends up in a small pond, where recently ducks have been seeking asylum.
It's has a good path for bicycles and can be an interesting way to experience the suburbs. The area is lovely in the summertime, though the various hills can make the bicycle trip a demanding one.
The area was the basis for the total incorporation of Iceland into Denmark-Norway in 1662.