A visitor takes pictures with a smartphone of an artwork entitled “Blue Europe, 2015” by Chinese artist Liu Bolin, on display during the exhibition “Visible Invisible” at the Mudec Museum in Milan on May 14, 2019. Liu Bolin known as “the invisible man” for his photographic self-portraits, focused on a body-painting blending with the surrounding area. (Photo by Miguel Medina/AFP Photo)

Iceland horses play on a meadow of a stud farm in Obernhain near Frankfurt, Germany, as the sun rises Thursday, July 23, 2020. (Photo by Michael Probst/AP Photo)

A hare runs on a small road as the sun rises in Frankfurt, Germany, Monday, June 12, 2023. (Photo by Michael Probst/AP Photo)

A woman carries an umbrella during a heat wave in Rome, Italy, 16 July 2023. Italy is facing the third heatwave of the summer on 16 July bringing record temperatures. The new heatwave is forecast to peak on 18 July, when temperatures in areas of southern Sardinian may reach 48 degrees Celsius, according to forecasts. On 15 July, the health ministry has put on red alert major Italian cities. (Photo by Massimo Percossi/EPA)

An Iraq fan poses before the World Cup 2022 Qualifier 2nd round Group C football match between Iraq and Iran at Amman International Stadium in Amman, Jordan on November 14, 2019. (Photo by Muhammad Hamed/Reuters)

The moon is seen in its waxing gibbous stage as it rises behind the helicopter from the original Batman television show, which people can ride at the New Jersey State Fair, Saturday, June 22, 2013, in East Rutherford, N.J. The moon, which will reach its full stage on Sunday, is expected to be 13.5 percent closer to earth during a phenomenon known as supermoon. (Photo by Julio Cortez/AP Photo)

Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

A woman spits red paint as if it is blood protesting against bullfights in Madrid, Spain on March 27, 2016. Anti-bullfighting protesters have turn the iconic square of “Puerta del Sol” into a bullring. Protesters, almost naked covered with red paint as if it was blood, have demanded the abolition of bullfights under the slogan “The bull suffers!”. (Photo by Marcos del Mazo/Pacific Press)