Swathes of Western Europe is wilting under intense heat, with socially-distanced crowds seeking relief in fountains and pools as authorities warn of COVID-19 and wildfire risks.
Temperatures in Paris reached a sweltering 40 degrees Celsius on Friday.
The few who dared to leave their homes looked for shade in parks.
An increase in COVID-19 cases prompted French officials to tighten face mask requirements in several cities this week this week, with many making them mandatory outdoors as well as in enclosed public spaces.
As Parisians began their annual holiday exodus from the capital, officials imposed driving restrictions to limit ozone pollution.
French authorities also urged families and neighbours to check in on the elderly. Retirement homes were placed on high alert after the use of air conditioning was discouraged over fears they could foster coronavirus contagions.
From Britain to Italy, temperatures nearing 40C (104 Fahrenheit) or more made face masks almost unbearable for many, as more cities begin requiring them outdoors to prevent surges in COVID-19 cases.
"Even in this stifling heat, it's better to put up with 38 degrees than catch the coronavirus," said Daniela Iannelli, a 55-year-old municipal employee in Rome.
Fourteen Italian cities were placed on high alert, while France issued warnings for around one-third of the country's 101 departments.
In the UK on what was the hottest day of the year so far at almost 38C, Britons crowded onto Brighton beach on the south coast.
City officials had urged visitors to stay away, saying it was impossible to maintain social distancing amongst the crowds.
But many ignored the advice; after weeks of lockdown misery it was just too tempting.
The Spanish weather service said most of the country was scorching under an air mass moving north from Africa, with Madrid reporting 38 degrees while several other cities in the interior saw 40 degrees or more.
Germany recorded its hottest day of the year on Friday with temperatures exceeding 35C in parts of the south.
In the Netherlands, beachgoers were told to avoid the coastal resort of Zandvoort near Amsterdam, with public safety authorities saying it was too crowded to maintain coronavirus social distancing.
"There are much quieter beaches on our coast and on other waters, I advise you to look for them," the regional safety authority chairperson Marianne Schuurmans was quoted as saying by Dutch media.
Western Europe can expect relief from the high temperatures from Saturday, forecasts show.