Greece shut more ancient tourist sites in Athens on Thursday and elderly people took refuge at designated air-conditioned spots as the first heatwave of the summer persisted for a third day.

The famous Acropolis, set on a rocky hill overlooking the capital, and other nearby tourist attractions were closed on Thursday afternoon as winds from North Africa pushed temperatures towards 43 degrees Celsius (109 degrees Fahrenheit).

Many primary schools and nurseries across the country were closed to protect students from the heat, which was expected to recede on Saturday. In Athens, tourists stopped at drinking fountains to cool their heads and necks. Locals sat in air conditioned rooms set up by the city, using hand held fans to create a breeze.

Firefighters who put out several wildfires on Wednesday remained on high alert as strong winds were expected to hit several parts of the country.

Greece is one of the most hard-hit countries by global warming in Europe, with rising temperatures fuelling deadly fires and erratic rains in recent years.

Athens, a city of five million people which sits in a coastal bowl jammed with apartment blocks and flanked by mountains, is one of the hottest cities in Europe.

Scientists warn that summer temperatures there could rise by an average of 2 degrees by 2050. Athens mayor Haris Doukas has tried to create more shade by planting 2000 trees.

Our first goal shall be to lower the median temperature, the felt-air temperature,” he told Reuters. “There are areas where the temperature is 15 or 20 times higher on cement or a city road, compared to a shady area.”