A boy poses with a butterfly on his face during a photocall to promote the “Sensational Butterflies” exhibition at the Natural History Museum in central London, on March 25, 2013. With around 400 live tropical butterflies and moths living in the temporary facility, visitors will get the chance to see them flying freely as well as looking for emerging butterflies at the hatchery window. Running from March 29 to September 15, 2013, the exhibition is housed in a structure in the museum grounds. (Photo by Leon Neal/AFP Photo)

Military vehicles surround a wreckage of a trolleybus, in Volgograd, Russia, Monday, December 30, 2013. A bomb blast tore through a trolleybus in the city of Volgograd on Monday morning, killing at least 10 people a day after a suicide bombing that killed at least 17 at the city's main railway station. Volgograd is about 650 kilometers (400 miles) northeast of Sochi, where the Olympics are to be held. (Photo by Denis Tyrin/AP Photo)

A woman carries her child as she watches Mount Sinabung volcano spewing thick volcanic ash, as seen from Karo on July 21, 2017. Sinabung roared back to life in 2010 for the first time in 400 years, after another period of inactivity it erupted once more in 2013, and has remained highly active since. (Photo by Gatha Ginting/AFP Photo)

This cable ropeway suspended between cliffs is the only access to Yushan village in Hubei Province, Chin, which has a population of just over 200 people. The ropeway was built in 1997; before that villagers faced a walk of several days to get to the next nearest village. The ropeway, which is powered by a diesel engine, is 1,000 metres long and 400 metres above the valley floor.

An African Penguin holds a Valentine's Day card at the California Academy of Sciences on February 13, 2013 in San Francisco, California. In honor of Valentine's Day, the colony of African Penguins at the California Academy of Sciences received heart-shaped red valentines with hand written messages from Academy visitors. (Photo by Justin Sullivan)

A dancer dressed for the annual procession honoring San Pedro, his town's patron saint, runs through the street of San Pedro Sacatepequez near Guatemala City June 29, 2016. (Photo by Saul Martinez/Reuters)

An officer wipes sweat off the face of a Chinese People's Liberation Army (PLA) honor guard soldier as they rehearse for a welcoming ceremony for New Zealand's Governor-General Sir Jerry Mateparae at the Great Hall of the People in Beijing, Tuesday, July 21, 2015. (Photo by Mark Schiefelbein/AP Photo)

Revelers celebrate during fireworks marking the start of the New Year on Copacabana beach on January 1, 2017 in Rio de Janeiro, Brazil. Brazilian revelers traditionally dress in white to honor the New Year's holiday along with the Brazilian Goddess of the Sea- Iemanja. (Photo by Mario Tama/Getty Images)