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)

Lukas Michul, a member of the “dream walker” group jumps from atop the rugged rocks overlooking the azure waters of Navagio beach, one of the Greece's most renowned leisure spots on the popular tourist island of Zakynthos on June 23, 2014. This is rope jumping – part diving, part rock climbing, with a touch of engineering. The aim of the project is to dream jump in 80 places with most ravishing nature and architecture all over the world .They plan to stage their next leaps at a cave complex in Croatia, a French viaduct, skyscrapers in Las Vegas and Johannesburg, and the Grand Canyon. (Photo by Louisa Gouliamaki/AFP Photo)

“The Lockheed SR-71 “Blackbird” was an advanced, long-range, Mach 3+ strategic reconnaissance aircraft. It was developed as a black project from the Lockheed A-12 reconnaissance aircraft in the 1960s by the Lockheed Skunk Works. Clarence “Kelly” Johnson was responsible for many of the design's innovative concepts. During reconnaissance missions the SR-71 operated at high speeds and altitudes to allow it to outrace threats. If a surface-to-air missile launch was detected, the standard evasive action was simply to accelerate and outrun the missile”. – Wikipedia

Photo: A U.S. Air Force SR-71A, also known as the “Blackbird”, is put through it's paces during a test flight over Beale Air Force Base in California. The aircraft is a strategic reconnaissance plane by Lockheed and is the world's fastest and highest flying operational aircraft. (Photo by Getty Images)

Kambeba Indian, Dream Braga, 18, aims his arrow in a jungle near the village Tres Unidos, Amazon state May 9, 2015. Dream Braga has been shooting fish with a bow and arrow for most of his life. In the Amazonian village where he grew up, that was what kids did for food and fun. He participated in the Indigenous Archery Project which recruits Amazon native children to compete with modern archery equipment and try for a place on the national team, with the 2016 Olympics in Rio de Janeiro as their ultimate goal. After training with Olympic coaches for three months, he has now been promoted to Brazil's national team. (Photo by Bruno Kelly/Reuters)

Birds fly over the Atomic Bomb Dome in Hiroshima, western Japan July 29, 2015. On August 6, 1945, the U.S. dropped the atomic bomb on Hiroshima, killing about 140,000 by the end of the year in a city of 350,000 residents, in the world's first nuclear attack. Three days later, a second atomic bomb was dropped on Nagasaki. Influenced by the shadows scorched into outdoor surfaces by the heat of the blasts 70 years ago, Reuters photographer Issei Kato pays homage to survivors, residents and historic buildings in both cities in a personal project that captures the shadows of today. (Photo by Issei Kato/Reuters)

A rat being trained by the Cambodian Mine Action Centre (CMAC) is pictured on an inactive landmine field in Siem Reap province July 9, 2015. Gambian pouched rats were deployed to Cambodia from Tanzania in April by a Belgian non-profit organization, APOPO, to help clear mines. They've been trained since they were 4 weeks old. Cambodia is still littered with landmines after emerging from decades of civil war, including the 1970s Khmer Rough “Killing Fields” genocide, leaving it with one of the world's highest disability rates. APOPO has used the rodents for mine-clearing projects in several countries, including Angola, Mozambique, Thailand, Laos, and Vietnam. (Photo by Samrang Pring/Reuters)

Girls, who are part of Afghan Mobile Mini Circus for Children (MMCC), participate in a juggling competition in Kabul, Afghanistan August 12, 2015. The MMCC, founded by David Mason from Denmark, teaches cooperation and creativity to children scarred by years of war in Afghanistan. Despite the dangers, the project has grown so popular that it now runs centres in ten provinces and has hundreds of regular students. The circus makes visits to internally displaced persons' camps, schools, orphanages, and holds annual festivals. The children are taught the skills of juggling clubs, walking on stilts and acrobatics. (Photo by Ahmad Masood/Reuters)

Hair stylist Marcelo Avatte (R) prepares to fit Isidora Serrano, a 14-year-old who lost her hair due to chemotherapy to treat her bone cancer, with a natural hair wig in the cancer ward of the Luis Calvo Mackenna Hospital in Santiago, October 23, 2014. The wigs, handmade by Italian-Chilean hair stylist Marcelo Avatte and his team, have helped the children regain their self-esteem and confidence during cancer treatment. Renowned for making customised wigs, Avatte has donated more than 300 wigs since 2009 and says he was motivated to begin the project by the pain he felt when his own son lost his hair during chemotherapy. (Photo by Rodrigo Garrido/Reuters)