Sweltering temperatures hit much of Western Europe on Tuesday as a ferocious heatwave headed north.
The UK hit its highest ever temperature of 40.3C, according to provisional Met Office figures, and forecasters warned temperatures were still climbing.
Extreme heat warnings were issued in France and record July temperatures were reported in the Netherlands.
Deadly wildfires in France, Portugal, Spain and Greece have forced thousands of people to evacuate their homes.
Two people were killed by forest fires in Spain's north-western Zamora region and trains in the area were halted because of fire near the tracks. An elderly couple died while trying to escape fires in northern Portugal.
Heatwaves have become more frequent, more intense, and last longer because of human-induced climate change. German Environment Minister Steffi Lemke said the climate crisis meant the country had to rethink its preparations for very hot weather, drought and flooding.
Wildfires were still burning a day after several French cities including Nantes in the west saw their hottest-ever day.
More than 30,000 people have had to flee, with several camp sites destroyed and emergency shelters set up for evacuees.
Gironde, a popular tourist region in the south-west, has been hit particularly badly, with firefighters from across France battling to control two blazes that have destroyed 19,300 hectares (47,700 acres) of land in the past week. The city of Bordeaux was blanketed by smoke early on Tuesday as the wind changed direction.
"It's a monster like an octopus, and it's growing and growing and growing in the front, in the back, on both sides," said Jean-Luc Gleyze, Gironde's regional president.
The hottest temperatures have now moved to the north and east. Hundreds of people have had to leave their homes in the far north-west of Brittany, and fire has destroyed 1,400 hectares of vegetation.
A dozen animals at the zoo in La Teste-de-Buch died of stress and from the high temperatures, the government said. In a complex operation involving vets, zookeepers and others, 363 animals that could be moved were driven in convoys to Bordeaux-Pessac zoo 65km (40 miles) away.
The UK's Met Office said 40.2C°C was provisionally recorded at Heathrow Airport west of London on Tuesday, and forecasters warned temperatures were still climbing in many places. Extreme heat warnings have been issued covering central, northern and south-east England.
Forecasters say the heatwave is heading north, with the mercury expected to hit 40C in the far south of Belgium as well as western and southwestern Germany. A fire broke out in dunes at the Belgian resort of De Haan, setting several vehicles alight.
Germany's DWD weather service recorded a national record temperature of 41.2C in the city of Duisburg in July 2019 and spokesman Andreas Friedrich said similar highs were possible on Tuesday in similar areas along the River Rhine.
The Netherlands saw one of its hottest days on record on Tuesday with 38.9C in Maastricht, forecasters said, warning that temperatures were continuing to rise.
In Spain and Portugal, more than 1,000 deaths have been attributed to the heat in recent days. A forest fire in Losacio in the north-west left one firefighter dead on Sunday and the body of a 69-year-old shepherd was found on Monday.
Temperatures in Portugal hit 47C on Thursday - a record for July. Most of the country has been placed under high fire danger by the national meteorological office IPMA.
Several villages were evacuated as a fire spread in the Murça area of northern Portugal, and a man and a woman in their 70s died in their car while trying to flee the flames.
Firefighters were fighting the blaze on three fronts and a local mayor said more than 3,000 hectares had been burned. Authorities are anxious to avoid a repeat of 2017, when 66 people were killed in wildfires.
In Spain, at least 20 fires are burning out of control. A passenger filmed the moment the train he was travelling on came to a temporary halt - as fires raged on both sides of the carriage near the northern border with Portugal.
Forecasters in Italy are warning of temperatures as high as 40 to 42C between Wednesday and Friday.
The effects of climate change in Europe were highlighted earlier this month when a melting glacier triggered an avalanche that killed 11 people. Now experts at Italy's IlMeteo warn that new crevasses are opening up on Alpine peaks and that ice is melting even on Western Europe's highest mountain, Mont Blanc.
The world has already warmed by about 1.1C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.