Four people died in Spain, two in France and two in Italy as an early summer heatwave continued to grip much of Europe on Wednesday, triggering health alerts and forest fires and forcing the closure of a nuclear reactor at a Swiss power plant.

Barcelona recorded its hottest June in over a century, the summit of Paris' iconic Eiffel Tower was closed to visitors and hundreds of French schools shut Tuesday as Europe sizzled in its first major heat wave of the summer.

A heatwave that has scorched large parts of Europe in recent days is beginning to subside. Alerts remain in place across multiple countries.