A new LED light fixture is secured to the side of a lift as crews replace existing street lights August 1, 2011 in Las Vegas, Nevada. The new energy-efficient fixtures are expected to reduce the city's annual electricity use by eight million kilowatt hours, saving about USD 400,000. The city estimates the LEDs will last about 15 years, nine years longer than the current lights. Funding for the project comes from federal energy conservation bonds and an American Recovery & Reinvestment Act grant. The city plans to replace all of its 50,000 streetlights after more funding is secured. (Photo by Ethan Miller/Getty Images)

A member of the United States Naval Academy freshman class crawls through trenches at the wet and sandy station during the annual Sea Trials training exercise at the U.S. Naval Academy on May 13, 2014 in Annapolis, Maryland. For 14 hours, the United States Naval Academy freshman class, also known as Plebes, worked as a team to complete many grueling physical and mental challenges that help prepare them for real-world experiences and reinforce leadership, bonds, trust, and teamwork. Of the challenges, they endured: a two-mile regimental run, ground fights, water tactics, aquatics challenges, and survival skills, amongst many others. (Photo by Patrick Smith/Getty Images)

A man holds a girl as she tries to escape when she realised she is to to be married, about 80 km (50 miles) from the town of Marigat in Baringo County, Kenya, December 7, 2014. As Pokot tradition dictates, the future husband arrived to her family home with a group of men to collect the girl. The men arrived with the last settled dowry of livestock for the girl's family. In this case it was 20 goats, three camels and 10 cows, given during a period of several weeks. (Photo by Siegfried Modola/Reuters)

Girls hold hands as they arrive their New Year parties in Newcastle, England on December 31, 2019. (Photo by Craig Connor/North News and Pictures)

Girls sits on a bench during summer at the Central Park in New York, United States, 2011. (Photo by An Rong Xu)

An Afghan girl harvests Cotton buds at a field on the outskirts of Balkh province, Afghanistan, November 15, 2014. (Photo by Sayed Mustafa/EPA)

“The girl behind the camera and the girl in front of the camera”, May 2012. (Photo by: Mandy Rosen; Source: Flickr)

Girls ride on a donkey cart with grass for animals on the outside of Nangarhar province, Afghanistan May 19, 2015. (Photo by Reuters/Parwiz)