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)

These adorable cats – which are twins – showcase their contrasting blue and green eyes. The cats have a condition called heterochromia iridis, which causes each eye to vary in color. (Photo by @sis.twins/Caters News Agency)

“A Hawaiian photographer braved freezing temperatures for this cold SNAP – of what appears to be a firebird bursting from an aurora. Keen snapper CJ Kale, more used to sun, sea and sand while at work than snow, captured the incredible moment while on a trip to Alaska. It was his first time seeing the spectacular sight and lucked out – capturing some of the rarest colors of aurora on his first night”. – Caters News

A tourist reacts as an elephant sprays her with water in celebration of the Songkran water festival in Thailand's Ayutthaya province, April 9, 2014. Songkran, the most celebrated festival of the year, marks the start of Thailand's traditional New Year. (Photo by Chaiwat Subprasom/Reuters)

“Photographer Max Ellis has become an internet star – after posting wacky photos of squirrels in hilarious situations, from being sent flying through the air in fear by a Buckaroo to lifting weights. Max places his self-made creations in his garden in Teddington, London, and then painstakingly waits hours – and sometimes days – for his subjects to get into the exact position to capture his shot. In another scene an inquisitive squirrel is sent backwards in surprise as a bottle of champagne pops its cork and in others a squirrel appears to saw his friend in half just like the famous magic trick”. – Caters News

An Amur tiger walks across a passageway after a news conference at the Philadelphia Zoo, Wednesday, May 7, 2014, in Philadelphia. The see-through mesh pathway called Big Cat Crossing is part of a national trend called animal rotation that zoos use to enrich the experience of both creatures and guests. (Photo by Matt Slocum/AP Photo)

This plane looks like it's bound for the moon as it shoots across the sky. Photographer Sebastien Lebrigand was impressed he could even see the lights on the jet's wings in this stunning silhouette. (Photo by Sebastien Lebrigand/Solent News)

The summit of one of Europe's tallest mountains glows like the flame of a candle as the sun rises on a clear morning. The Matterhorn, famous for appearing on bars of Toblerone chocolate bars, reflects the vivid orange light at 5.37am. (Photo by Margarethe Jaeger/Solent News & Photo Agency)