An adult helps a young girl light a cigarette as a band plays in the background in the village of Vale de Salgueiro, northern Portugal, during the local Kings' Feast Friday, January 5, 2018. The village's Epiphany celebrations, called Kings' Feast, feature a tradition that each year causes an outcry among outsiders: parents encourage their children, some as young as 5, to smoke cigarettes. (Photo by Armando Franca/AP Photo)

Urban photographer Roman Robroek spent five years scouring the continent for the grandest examples of forgotten architectural beauty. Here: Watch your step on this Polish spiral staircase. (Photo by Roman Robroek/South West News Service)

The Sculpture Bank (2017) by Chinese artist Mu Boyan is exhibited along the Bondi to Tamarama Coastal walk as part of the Sculpture by the Sea exhibition in Sydney, Australia, October 18, 2018. (Photo by Charlotte Curd/The Guardian)

Germany, Business couple making love under desk. (Photo by Roman Maerzinger/Getty Images)

A woman carrying an inflatable doll crosses Withy Grove in Manchester, UK on September 11, 2016. Revellers out in Manchester City Centre. (Photo by Joel Goodman/London News Pictures)

Estonia's olympic team female marathon runners triplets (L-R) Lily, Liina and Leila Luik run during a training session in Tartu, Estonia, May 26, 2016. Leila, Liina and Lily Luik will make Olympics history as the first identical triplets to compete against each other when they cross the start line for the women's marathon in Rio. (Photo by Ints Kalnins/Reuters)

The common brushtail possum (Trichosurus vulpecula, from the Greek for "furry tailed" and the Latin for "little fox", previously in the genus Phalangista) is a nocturnal, semi-arboreal marsupial of the family Phalangeridae, it is native to Australia, and the second largest of the possums.

“Kilauea Rules”. The most extreme place we put ours kayakers to paddle till now. Photo location: Big Island, Hawaii. (Photo and caption by Alexandre Socci/National Geographic Photo Contest)