Millions of people in the UK are bracing for extreme temperatures, as a heat wave engulfs much of Europe.
And - for the first time ever - British authorities have issued a ‘red warning’, saying temperatures could soar to 41 degrees.
With more, here’s our World News Editor, Kate Gregan.
It's so hot it's officially a national emergency.
And with extreme heat comes a high risk to health.
Professor Emily Shuckburgh from Cambridge University told Channel 4, that these temperatures are a silent killer.
"This sort of heat is quite simply deadly.
"When we have seen heatwaves in the past in this country, in 2020 there were more than 2500 heat-related deaths.
"It particularly affects the elderly but if you are pregnant, if you have a baby then you will realise how difficult it is to survive in this kind of temperature."
Some schools are closing early – or not opening at all – and in the capital, Londoners have been warned not to travel.
Today FM’s resident Brit, Lydia Batham, explains why getting on the tube during a heatwave is such a bad idea:
"It can be so unbearable in the heat, I remember being on the central line on a really hot day and you are just dripping in sweat, everyone around you is, it's just uncomfortable.
"The tube gets really busy, you're rammed up against people, you are quite far underground as well, it's just a recipe for disaster in the heat."
Authorities are also concerned the temperatures will cause train tracks to buckle… and some rails are being painted white so they absorb less heat.
Plus, water companies have warned that increased demand is leading to low pressure - and even interrupting supply for some households.
Countries like Australia, Qatar or Morocco are used to these kinds of temperatures.
And UNLIKE the UK - their infrastructure is designed to withstand hot weather.
Only around 3 percent of homes in Britain have air conditioning - and homes are designed to keep heat IN – not OUT.
The country’s Health Minister, Steve Barclay says it will be a very tough week, and people need to prepare.
"The clear message to the public is to take sensible steps in terms of water, shade and cover that many people are aware of that's the best way of mitigating the heat.
"We're asking people to keep an eye out for their neighbours and those who may be vulnerable."
Scientists say heatwaves have become more frequent, more intense, and last longer because of climate change.
The world has already warmed by about 1.1 degrees since the industrial era began, and experts predict that temperatures will keep rising unless governments make steep cuts to emissions.
