A prototype Rollkers transportation device is displayed during a press event at the Mandalay Bay Convention Center for the 2015 International CES on January 4, 2015 in Las Vegas, Nevada. The product is not a skate; it balances for you and when you place it on the bottom of your shoe, it gives you the ability for faster transportation based on walking. The balance CES, the world's largest annual consumer technology trade show, runs from January 6-9 and is expected to feature 3,600 exhibitors showing off their latest products and services to about 150,000 attendees. (Photo by Ethan Miller/Getty Images)

Revellers parade for Gavioes da Fiel samba school during carnival in Sao Paulo, Brazil, February 6, 2016. (Photo by Paulo Whitaker/Reuters)

Injured horses huddle together in Oklahoma City on Monday. (Photo by Chris Landsberger/The Oklahoman)

Chinese artist Kong Ning poses in a costume symbolizing a butterfly, which is decorated with 365 masks on its wings to represent the number of days in a year, during her performance art at the Badaling section of the Great Wall on the outskirts of Beijing January 1, 2015. Kong, whose works include themes related to China's air pollution problem, named her new performance art “Hua Die” (transforming into a butterfly) and performed it on the first day of the new year as she hopes that China has clean air for this year. (Photo by Kim Kyung-Hoon/Reuters)

Ukrainian soldiers of the 71st Jaeger Brigade fire a M101 howitzer towards Russian positions at the frontline, near Avdiivka, Donetsk region, Ukraine, Friday, March 22, 2024. (Photo by Efrem Lukatsky/AP Photo)

Brazilian model and TV presenter Sabrina Sato from the Gavioes da Fiel samba school performs during a Carnival parade in Sao Paulo, Brazil, Sunday, February 11, 2024. (Photo by Andre Penner/AP Photo)

A Naga sadhu, or naked Hindu holy man, poses for a picture after taking a holy dip in the Godavari River during Kumbh Mela, or Pitcher Festival, at Trimbakeshwar in Nasik, India, Sunday, September 13, 2015. Hindus believe taking a dip in the waters of a holy river during the festival, will cleanse them of their sins. According to Hindu mythology, the Kumbh Mela celebrates the victory of gods over demons in a furious battle over a nectar that would give them immortality. (Photo by Rafiq Maqbool/AP Photo)

A machine works on a Rio 2016 Olympic medal at the Casa da Moeda do Brasil (Brazilian Mint) in Rio de Janeiro, Brazil, June 28, 2016. The Casa da Moeda do Brasil is the Brazilian mint, owned by the Brazilian government and administratively subordinated to the Ministry of Finances. It was established in 1694. (Photo by Sergio Moraes/Reuters)