1: Dubai's Burj Khalifa is the tallest building in the world, but perhaps not for long. Saudi Arabia has announced plans to build a 1 kilometer (3,280 foot) tower into the sky, to be named the Jeddah Tower, scheduled for completion in 2020. The Burj Khallifa currently stands at 2,716 ft. (Photo by Matthias Seifert/Reuters)

The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)

U.S. players push head coach Adam Krikorian into the pool after they defeated the Netherlands in their women's water polo gold medal match during the Aquatics World Championships in Kazan, Russia, August 7, 2015. (Photo by Michael Dalder/Reuters)

Comic club member Michael Kenney pauses on South Broad Street to adjust his costume during the 116th annual Mummers Parade in Philadelphia on Friday, January 1, 2016. Outrageously costumed Mummers strutted their stuff Friday at the city's annual New Year's Day parade, a colorful celebration that features string bands, comic brigades, elaborate floats and plenty of feathers and sequins. (Photo by Joseph Kaczmarek/AP Photo)

TV host/blogger Louise Roe attends The Weinstein Company's Academy Awards viewing and after party in partnership with Grey Goose at TAO Los Angeles at TAO Hollywood on February 26, 2017 in Los Angeles, California. (Photo by Rachel Murray/Getty Images for The Weinstein Company)

A traffic policeman hides a rose behind his back before giving it to a female driver ahead of International Women's Day in Ryazan, Russia on March 7, 2017. (Photo by Alexander Ryumin/TASS via Getty Images)

Lily Aldridge and Stella Maxwell arrive at the Daily Front Row's 3rd Annual Fashion Los Angeles Awards at the Sunset Tower Hotel on April 2, 2017 in West Hollywood, California. (Photo by Jon Kopaloff/FilmMagic)

North Korean women soldiers take part in a military parade Saturday, April 15, 2017, in Pyongyang, North Korea, to celebrate the 105th birth anniversary of Kim Il Sung, the country's late founder and grandfather of current ruler Kim Jong Un. (Photo by Wong Maye-E/AP Photo)