Altreu is a small village on the Aare west of Solothurn, famous for the white storks that nest on rooftops, poles, and tall trees around the settlement. The colony began as a reintroduction project in the 1940s and has become one of the more quietly charming wildlife stops in the canton.
This is not a spectacle on the scale of the Verena Gorge or the cathedral, but it is a good half-day excursion if you are cycling or walking along the river. The Witi information centre explains the storks and the protected agricultural landscape around them, and the village is most rewarding in spring and early summer when the nests are active.