A Humboldt penguin stands on weighing scales whilst being photographed by members of the press during a photocall at the annual weigh-in at London Zoo in London, Britain, 24 August 2016. Every animal that is in the zoo is weighed and measured and the statistics recorded so the data can be shared with zoos across the world. (Photo by Hannah McKay/EPA)

A Balinese Hindu blows fire, during a parade carrying Ogoh-ogoh effigies symbolising evil spirits, during a ritual before Nyepi, the day of silence, in Palembang, South Sumatra province, Indonesia March 8, 2016. Nyepi is a day of silence for self-reflection celebrating the Balinese Hindu new year, where people may not use lights, light fires, work, travel nor enjoy entertainment. (Photo by Darren Whiteside/Reuters)

A hot air balloon in the likeness of Yoda from Star Wars prepares for liftoff at the 21st Philippine International Hot Air Balloon Festival at the former Clark US Air Force base in Pampanga Province, Philippines on February 9, 2017. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

Employees of a food stand take pictures of Titan, a robot created by England Cyberstein Robots, performing at the Danilovsly market in downtown of Moscow, Russia, 12 May 2014. Titan visited to Moscow to attend “Bal Robotov”, an interactive exhibition of the most recent advances in robotics which will be opened on 15 May in Artplay Moscow exhibition center. Titan worked alongside superstars including Will.i.am, Rihanna, Will Smith and Jackie Chan. (Photo by Sergei Ilnitsky/EPA)

Protesters clad in improvised protective gear prepare for a clash with police in central Kiev, Ukraine, Monday, January 20, 2014. After a night of vicious streets battles, anti-government protesters and police clashed anew Monday in the Ukrainian capital Kiev. (Photo by Evgeny Feldman/AP Photo)

Two men fight in San Jose, Costa Rica, during the Women's Day on March 8, 2014. (Photo by Jeffrey Arguedas/EFE/SIPA Press)

In this image distributed on Tuesday, September 29, 2015, 11-year old dance star Taylor Hatala and friends are seen filming their new Monster High Boo York, Boo York music video #CityGhouls in Los Angeles. (Photo by Casey Rodgers/Invision for Mattel/AP Images)

“Freedom”. After the 30 years banning import large motorcycle, in 2007, the Taiwan government reopened the import licensing of the motorcycle displacement over 550 cubic centimeter. Those large bikes, which were never seen before, were strange thought and treated unequally frequently. However, those adversity will not stop those enthusiastic bike riders from chasing the road of freedom. Photo location: Taiwan. (Photo and caption by 火花 羅/National Geographic Photo Contest)