A worker pauses for a sandwich, resting on a girder during the construction of a skycraper. (Photo by Hulton Archive/Getty Images). Circa 1930

A tourist walks inside the Ice Palace glacier hollow at Hintertux glacier, located at around 3250 meters above sea level, in Zillertal, Austria, 02 March, 2016. The hollow's temperature remains constant at 0 degrees Celsius, in summer and winter alike, and is also used by the University of Innsbruck for scientific research projects. (Photo by Lisi Niesner/EPA)

Chinese tourists watch storm clouds moving along the coast towards the city of Sydney, Australia, November 6, 2015. Powerful storms swept across the city on Friday, with the Australian Bureau of Meteorology issuing a warning for severe thunderstorms with large hailstones, heavy rainfall and damaging winds, local media reported. (Photo by David Gray/Reuters)

Dubai is now home to what has been billed as the world’s largest indoor dog park, complete with customised luxury suites, 24/7 webcams, flat screen TVs and orthopedic mattresses. Launched during Easter at Dubai Investment Park, My Second Home already has many takers with 40 of its 200 residential luxury rooms booked for summer. Here: a dog sits on its bed at My Second Home, a newly opened luxury pet resort and spa, in Dubai, April 24, 2015. (Photo by Ahmed Jadallah/Reuters)

A giant river otter, the world's largest otter species, looks out of its enclosure at the newly completed River Safari in Singapore, on March 25, 2013. (Photo by Wong Maye-E/Associated Press)

An alligator is skinned at All American Gator August 16, 2006 in Pembroke Park, Florida. The company processes gators for their skins, meat and trophies and was at full capacity a day after the start of gator hunting season. This year more than 4,000 licenses were sold with each license allowing hunters to kill two gators. The hunt has been expanded by 41 days over previous years, running August 15 to November 1. (Photo by Joe Raedle/Getty Images)

A view of the spectacular colour of clouds at sunset on January 17, 2005 in Beijing, China. (Photo by China Photos/Getty Images)