Italy placed all its major cities under the highest heat alert Thursday as a blistering heatwave gripped Europe, setting a national temperature record in Austria, fuelling wildfires in France and disrupting energy and transport systems across the continent. Read moreEurope's record-breaking heat sparks wildfires, drought in France, Greece and the UK The extreme weather has pushed temperatures above 40 Celsius (104 Fahrenheit) in several countries, prompting health warnings for millions of people. Scientists and officials warn that such events are becoming more frequent and intense as the climate warms. The current heatwave has exposed vulnerabilities in public health systems, power generation, transportation networks and tourism infrastructure, forcing governments and businesses to adapt to more frequent periods of extreme weather. Read more'I spent the night coughing': Wildfire smoke leaves Bordeaux residents struggling to breathe Italy’s Health Ministry placed all 27 cities monitored under its national heat surveillance system on red alert Thursday – the first time this year that the entire network has been under the highest warning level simultaneously. The alerts stretch from Trieste in the northeast to Palermo in Sicily and signal a health risk for the entire population, not only vulnerable groups such as older adults and people with chronic illnesses. Authorities urged residents and tourists to avoid direct sunlight during the hottest hours of the day, remain indoors where possible and drink plenty of water. The heat has also forced adjustments at major tourist attractions. The ministries of tourism and culture extended evening opening hours at landmarks including Rome’s Colosseum and Pantheon. Cooling mist fans have been installed at the Colosseum’s entrances and additional medical stations have been made available. Rome has also introduced another unusual response to the heat emergency: a free municipal “urban beach” along the Tiber River in the Marconi neighborhood, where residents can cool off in swimming pools, water fountains and shaded areas. The site, known as Tiberis, has become a refuge for families and children seeking relief from record temperatures. Residents praised the initiative, saying it allowed them to better cope with the heat and offered a rare opportunity to escape the city’s scorching asphalt and concrete. “It is excellent, it is a great initiative. They did the right thing, specially with such hot days it is important to cool down with water, specially for children," Rome resident Claudio Rocchi said. Slovakia shuts down its biggest hydroelectric power plant Later on Thursday, Slovakia recorded another all-time high temperature. The new record set at Dolne Plachtince in the south was 42.2 C (108 F), the Slovak Meteorological Institute said. In Slovakia, the low levels of water in the Danube forced the country’s biggest hydroelectric power plant in Gabčíkovo to shut down seven of its eight turbines, the TASR news agency said. So far this year, the power plant produced 15 percent less electricity than a year ago due to a lack of water in the river.