An aerial view shows sailing boats at the shores of the Silbersee lake on a hot summer day in Haltern...
An aerial view shows sailing boats at the shores of the Silbersee lake on a hot summer day in Haltern, Germany, July 4, 2015. A widespread, long-lasting heatwave will affect much of France, Britain, Belgium, the Netherlands and western Germany. REUTERS/Ina Fassbender