The northern lights, or aurora borealis, appear in the sky over the Bamburgh lighthouse at Stag Rock in Northumberland, England on September 28, 2016. (Photo by Owen Humphreys/PA Wire via ZUMA Press)

Students walk to school on the first day of their new school year in Giza, south of Cairo, Egypt September 25, 2016. (Photo by Mohamed Abd El Ghany/Reuters)

Model Alessandra Ambrosio poses for photographers during the red carpet for the movie “Spotlight” at the 72nd Venice Film Festival in northern Italy, September 3, 2015. (Photo by Stefano Rellandini/Reuters)

Brooke Candy attends the VFILES show during New York Fashion Week at Barclays Center of Brooklyn on September 6, 2017 in New York City. (Photo by Roy Rochlin/Getty Images)

Doutzen Kroes and Candice Swanpoel arrive at the Mert Alas x Marcus Piggot book launch party at Public Hotelon September 7, 2017 in New York City. (Photo by Pierre Suu/GC Images)

A model presents a creation from the Liu Bolin Debut collection during New York Fashion Week in the Manhattan borough of New York City, U.S., September 10, 2017. (Photo by Amr Alfiky/Reuters)

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

A propaganda troupe perform a flag- waving routine outside the central railway station in Pyongyang, North Korea on September 27, 2017. (Photo by Ed Jones/AFP Photo)