Complex sentence: Willisau is a municipality in the district of Willisau in the canton of Lucerne in Switzerland, formed on 1 January 2006 from the municipalities of Willisau Country and Willisau City.
Split into simpler sentences: Willisau is a municipality in the district of Willisau in the canton of Lucerne in Switzerland. It was formed on 1 January 2006 out of the union of the previously separate municipalities of Willisau Country and Willisau City.