In this two photo combination picture, the Eiffel Tower with its usual lighting at left, and after the lighting was switched off at right, at the occasion of the Earth Hour, in Paris, France, Saturday March 28, 2015. This Saturday, 28 March 8:30 p.m. local time, individuals, businesses, cities and landmarks around the world are switching off their lights for one hour to focus attention on climate change. (Photo by Remy de la Mauviniere/AP Photo)

A solar-powered plane takes off from Jiangbei International Airport in southwest China's Chongqing Municipality, Tuesday, April 21, 2015. The Solar Impulse 2 departed Chongqing on Tuesday for a 1190-kilometer (642-mile) flight to the city of Nanjing in eastern China, the sixth leg of its around-the-world flight. (Photo by Chinatopix via AP Photo)

People spray water in the street ahead of “Songkran”, the annual Thai New Year water-throwing festival, in Kowloon City, Hong Kong, China, 09 April 2017. The pouring of water is a key element in the festival as it represents purification and the washing away of one's sins and bad luck for the year. The event also includes a “Miss Songkran” pageant where contestants are clothed in traditional Thai dress, and a winner is crowned. This year's “Songkran” will begin in Thailand on 13 April 2017. (Photo by Alex Hofford/EPA)

In this May 12, 2017 photo, Pupy, an African elephant, stands in the doorway of his enclosure at the former city zoo now known as Eco Parque in Buenos Aires, Argentina. A year ago the 140-year old Buenos Aires zoo closed its doors and was transformed into a park. The first director decided that the animals should be housed in buildings that reflected their countries of origin. A replica of a Hindu temple was built for the Asian elephants. (Photo by Natacha Pisarenko/AP Photo)

Civilians present their rations cards in order to receive humanitarian food aid being distributed by the Iraqi Red Crescent, in the eastern side of Mosul, Iraq, Tuesday, January 31, 2017. Iraqi forces declared Mosul's eastern half fully liberated, just over three months after the operation to retake the city from IS was formally launched in October. (Photo by Khalid Mohammed/AP Photo)

Igor, a 40 year-old Ukranian soldier embraces his wife in front of his military basement in the center of Odessa on March 17, 2022. Odessa, which Ukraine fears could be the next target of Russia's offensive in the south, is the country's main port and is vital for its economy. But the city of one million people close to the Romanian and Moldovan borders also holds a special place in the Russian imagination. (Photo by Bulent Kilic/AFP Photo)

A person waves a drum while other people wearing traditional Russian village-style clothes celebrate the summer solstice near a bonfire in the village of Okunevo, about 200 kilometers (about 125 miles) northeast of the Siberian city of Omsk, Russia, on Wednesday, June 21, 2023. The festivities of Ivan Kupala, or John the Baptist, are similar to Mardi Gras and reflect pre-Christian Slavic traditions and practices. (Photo by Evgeniy Sofiychuk/AP Photo)

People cool off as they dance in a swimming pool in an event at a local restaurant during a heatwave on July 2, 2023 in Beijing, China. China's capital city and northern parts of the country have experienced unseasonably high temperatures in the last days, sometimes reaching more than 40 degrees celsius, causing local governments to issue heat warnings. (Photo by Kevin Frayer/Getty Images)