The Aurora Borealis (Northern Lights) lights up the sky near the village of Pallas (Muonio region) of Lapland, Finland September 8, 2017. (Photo by Alexander Kuznetsov/Reuters/All About Lapland)

Student Rabindra Bharati University celebrates the Holi festival, Color Festival on February 26, 2018 in Kolkata, India. Holi, the popular Hindu spring festival of colours is observed in India at the end of the winter season on the last full moon of the lunar month, and will be celebrated on March 1 this year. (Photo by Debajyoti Chakraborty/NurPhoto via Getty Images)

Indian students smear coloured powder during an event to celebrate the Hindu festival of Holi in Kolkata on February 26, 2018. Holi, the popular Hindu spring festival of colours is observed in India at the end of the winter season on the last full moon of the lunar month, and will be celebrated on March 1 this year. (Photo by Dibyangshu Sarkar/AFP Photo)

An aerial view shows a Russian Troika, a sledge drawn by three horses, competing on the ice-covered Yenisei River during the annual Ice Derby amateur horse race near the Siberian settlement of Novosyolovo, south of Krasnoyarsk, Russia March 17, 2018. (Photo by Ilya Naymushin/Reuters)

A woman mourns over the coffin of a relative after a deadly eruption of Mount Sinabung in Sukandebi village, Karo, North Sumatra, Indonesia May 22, 2016, in this photo taken by Antara Foto. The volcano in western Indonesian unleashed hot clouds of ash on Saturday, killing several villagers, an official said. (Photo by Irsan Mulyadi/Reuters/Antara Foto)

U.S. Secretary of State John Kerry and Mongolian Foreign Minister Lundeg Purevsuren watch an archer during a Naadam ceremony, a competition which traditionally includes horse racing, Mongolian wrestling and archery, in Ulan Bator, Mongolia, June 5, 2016. (Photo by Saul Loeb/Reuters)

People carry lychee for sale on a motorbike on a street in Luc Ngan, Bac Giang province, Vietnam, 22 June 2016. Lychee output in Bac Giang province is expected to reach 130,000 tonnes this year. China is still Vietnam's main lychee export market so far, buying around 60 percent of the annual crop, according to official reports. (Photo by Luong Thai Linh/EPA)

Participants share a moment after performing at a cultural program during India's Independence Day celebrations in Ajmer, in the desert state of Rajasthan, India, August 15, 2016. (Photo by Himanshu Sharma/Reuters)