An extreme heatwave has brought high temperatures and dry conditions to Greece, with 81 wildfires starting in the country over the last 24 hours.

The biggest fire, in a forest north of Athens, entered a residential area. Thousands of people have left their homes, and because of the smoke and flames, there has been a partial closure of the main north-south highway through Greece. There are 500 firefighters working to put out the blaze, which is being fueled by strong winds. Officials are hoping the winds die down by Wednesday morning, giving firefighters the chance to use more water-dropping aircraft.

Civil Protection Chief Nikos Hardalias said Greece is “undergoing one of the worst heatwaves of the past 40 years”, with temperatures in Athens reaching 113 degrees Fahrenheit. This is putting a strain on the country’s power supply, and forcing early closures at historical sites like the Acropolis.