On Wednesday, Belgium endured its hottest day ever recorded, with temperatures rising to 39.9 degrees Celsius (102 Fahrenheit). The Netherlands broke a 75-year record on Wednesday, and then hit another all-time high of 40 Celsius (104 Fahrenheit) on Thursday, the national weather forecasting institute
said. Temperatures there are still climbing.
In the German town of Geilenkirchen, a temperature high of 40.5 degrees Celsius (104.9 Fahrenheit) was recorded on Wednesday. The UK experienced its hottest ever July day on Thursday, with temperatures predicted to beat the hottest ever recorded temperature of 38.5 Celsius, set in 2003.
All four countries remain on extreme heat alert.
In June, a heat wave broke temperature records in eight countries, including France, the Czech Republic and Switzerland.
France reached a scorching 45.9 degrees Celsius (114.6 Fahrenheit). The country is on high alert again, with temperatures of 42 Celsius (107.6 Fahrenheit) expected in Paris.
The current heat wave presents a serious threat to Notre Dame Cathedral
. The roof of Paris’ beloved cathedral, which survived a massive fire months ago, is at risk of collapse, according to chief architect Philippe Villeneuve.
“What I fear is that the joints or the masonry, as they dry, lose their coherence, their cohesion and their structural qualities and that all of sudden, the vault gives way,” he said.
Story by CNN’s Isabelle Gerretsen and Jessie Yeung.