A heatwave is sweeping across parts of southern Europe and north-west Africa, with potential record-breaking temperatures in the coming days.
Temperatures are expected to surpass 40C (104F) in parts of Spain, France, Greece, Croatia and Turkey.
In Italy, temperatures could reach as high as 48.8C (119.8F). A red alert warning has been issued for 10 cities, including Rome, Bologna and Florence.
On Tuesday, a man in his forties died after collapsing in northern Italy.
Italian media reported that the 44-year-old worker was painting zebra crossing lines in the town of Lodi, near Milan, before he collapsed from the heat. He was taken to hospital where he later died.
"We are facing an unbearable heatwave," Italian politician Nicola Fratoianni tweeted.
"Maybe it's the case that in the hottest hours, all the useful precautions are taken to avoid tragedies like the one that happened today in Lodi."
People have been advised to drink at least two litres of water a day and to avoid coffee and alcohol, which are dehydrating.
One group of tourists on the streets of Rome told the Reuters news agency they were using sprinklers and thermal water as part of efforts to keep themselves cool.
"We're trying to survive," said Mariko Desso, who was visiting from the southern city of Bari.
Several visitors to the country have already collapsed from heatstroke, including a British man outside the Colosseum in Rome.
The Cerberus heatwave - named by the Italian Meteorological Society after the three-headed monster that features in Dante's Inferno - is expected to bring extreme conditions in the next few days.
Spain has been sweltering for days in temperatures of up to 45C and overnight temperatures in much of the country did not drop below 25C. Parts of Majorca on Wednesday were as high as 37C at 04:00.
The Andalusian regional government has started a telephone assistance service for people affected by the heat which has received 54,000 calls since it opened in early June. On the Spanish island of Majorca, the emergency health hotline has had to deal with more than one case of heatstroke every day since May.
A satellite image recorded by the EU's Copernicus Sentinel mission revealed that the land temperature in the Extremadura region had hit 60C on Tuesday.
"It is true that the temperatures have risen, but much, much higher than in other years," Madrid resident Alejandrina Coy told Reuters.
"I see that this is affecting everyone a lot."
"The weather is becoming less and less linear, there is less difference between the seasons," said Paz Llanes, another resident.
The Met Office says temperatures will peak on Friday, and BBC Weather says large swathes of southern Europe could see temperatures in the low to mid 40s - and possibly higher.
The heat is likely to continue into the weekend, and in Prague, the Czech capital, temperatures could reach as high as 36C (96.8F) on Saturday, according to BBC Weather - well up from averages of 24C (75.2F) in July.
But as Cerberus dies out, Italian weather forecasters are warning that the next heatwave, dubbed Charon after the ferryman who delivered souls into the underworld, will push temperatures back up towards 43C in Rome and a possible 47C on the island of Sardinia.
Europe's hottest-ever temperature of 48.8C (119.8F) was recorded near Syracuse on the Italian island of Sicily in August 2021.
A new study says 61,672 people died in Europe as a result of the heat last year. ISGlobal Institute in Barcelona said Italy had most deaths that could be attributable to the heat, with 18,010, while Spain had 11,324 and Germany 8,173.
The fear is that this heatwave could cause many more deaths this summer.
ISGlobal's research shows that that the cities in Spain with the highest risk of deaths caused by the heat are Madrid, Barcelona, Valencia, Sevilla, Málaga, Murcia, Palma de Mallorca and Bilbao.
A heatwave is a period of hot weather where temperatures are higher than is expected for the time of year.
Experts say periods of exceptionally hot weather are becoming more frequent and climate change means it is now normal to experience record-breaking temperatures.
The European Centre for Medium-Range Weather forecasts said that globally, this June was the hottest on record.