Extreme heat in Europe has been blamed for hundreds of deaths, a national monument has been shuttered in Greece and millions of Americans are under heat warnings from the National Weather Service as a scorching July gets underway around the world.

Greek authorities have taken a public protection decision: in the context of a severe heat wave affecting the entire country, the Acropolis in Athens will close during the hottest hours of the day. The decision comes amid an increased risk of fires and temperatures forecast to reach 42°C.

Major heat waves across southern Europe have pushed temperatures above 104 degrees Fahrenheit (40 degrees Celsius) in countries including Italy, Spain and Greece, as local authorities issued fresh warnings against the risk of wildfires.

On Monday, clear and warm weather is forecast. Winds in the Aegean Sea north northwest 4 to 6 Beaufort, light in the Ionian Sea. The temperature will rise slightly, reaching 39 to 40 degrees in the mainland and locally 41 degrees in areas far from the sea.

On Tuesday, Florence bore the full force of soaring temperatures, as thermometers topped an oppressive 38 degrees, causing a blackout in the city centre due to the excessive demand for electricity. Energy provider Enel confirmed it was able to swiftly restore power courtesy of their emergency measures in place.