Matthias Broda, inventor and designer of the wooden e-bike, cycles a prototype along a street in Berlin, November 20, 2014. The wooden e-bike produced by German company Aceteam from ash wood, will be launched on the market by spring 2015 and will cost around 3,950 euro (4,950 dollars). The e-bike will be equipped with an 250W e-bike motor for a range of up to 100 kilometer (62 miles) with a rechargeable battery. (Photo by Fabrizio Bensch/Reuters)

Secondary school students perform a barefoot “pilgrimage of suffering” to support the Occupy Central civil disobedience movement at the Admiralty protest site in Hong Kong November 30, 2014. It has been two months since police first fired tear gas to disperse demonstrators from the main protest site in the Admiralty district next to government offices in the heart of the Asian financial centre. (Photo by Bobby Yip/Reuters)

A long-tailed macaque grabs a necklace from a statue during the annual Monkey Buffet Festival at the Pra Prang Sam Yot temple in Lopburi, north of Bangkok November 30, 2014. The festival provides food and drinks to the local monkey population, which numbers more than 2,000, to thank them for drawing tourists to the town. (Photo by Damir Sagolj/Reuters)

This artist image released from Japan's airline All Nippon Airways (ANA) on April 17, 2015 shows ANA's Boeing 787-9 aircraft into the colors of R2-D2 robot of Star Wars. Japanese air carrier ANA will place the special colored jetliner in service in this autumn. (Photo by AFP Photo/All Nippon Airways)

A solar-powered plane takes off from Jiangbei International Airport in southwest China's Chongqing Municipality, Tuesday, April 21, 2015. The Solar Impulse 2 departed Chongqing on Tuesday for a 1190-kilometer (642-mile) flight to the city of Nanjing in eastern China, the sixth leg of its around-the-world flight. (Photo by Chinatopix via AP Photo)

People look at smoke and flame rising from the Nevskaya Manufaktura textile factory founded by English merchant J. Thornton in 1841, in St. Petersburg, Russia, Monday, April 12, 2021. The emergencies ministry said the fire had broken out over several floors of the red-brick Nevskaya Manufaktura building on the Oktyabrskaya Embankment of the Neva River. (Photo by Dmitri Lovetsky/AP Photo)

A Sadhu, Hindu holy person, prepares himself by smearing ashes on his body during the Maha Shivaratri festival at the Pashupati Temple in Kathmandu, Nepal, 11 March 2021. The Maha Shivratri festival, which is celebrated on 11 March, sees Hindu devotees, from across the country and neighboring India, gather to celebrate the birthday of Lord Shiva, the Hindu god of creation and destruction, by offering special prayers and fasting. (Photo by Narendra Shrestha/EPA/EFE)

People stand and take selfies in front of lava from the eruption of Mount Nyiragongo, in Buhene, on the outskirts of Goma, Congo in the early hours of Sunday, May 23, 2021. Congo's Mount Nyiragongo erupted for the first time in nearly two decades Saturday, turning the night sky a fiery red and sending lava onto a major highway as panicked residents tried to flee Goma, a city of nearly 2 million. (Photo by Justin Kabumba/AP Photo)