Temperatures are nearing record-breaking levels in Italy, Spain and Greece, as well as parts of the United States and Japan. Weather experts warn scorching weather will likely continue into next week.
Dozens of cities across southern Europe were under heat wave warnings Saturday, as officials warn of extreme temperatures persisting over the coming days.
In Italy, at least 16 cities were under "red" alerts for heat, including Rome, Florence and Bologna.
In the southern Italian islands of Sicily and Sardinia, temperatures were set to soar to 48 degrees Celsius (118 degrees Fahrenheit).
That would make it the hottest temperature ever recorded in Europe, according to the European Space Agency, whose satellites monitor land and sea temperatures.
The temperature was expected to hit 40 degrees Celsius in Rome on Monday and perhaps climb higher on Tuesday, smashing the 2017 records of 40.5 degrees Celsius in Italy's capital.
In Greece, the Acropolis was partially closed for a second day, with the national weather service warning that "parts of the country could see highs as much as 44 degrees Celsius on Saturday."
The service said the heat wave warnings would continue into next week.
In Spain, the national meteorological service said temperatures in the eastern Iberian Peninsula and the Balearic Islands would rise to between 40 and 42 degrees Celsius.