Women perform square dancing at a park square in Beijing, China, April 9, 2015. Chinese-style square dancing is running circles around other hobbies for the elderly, with millions taking to parks and plazas across China, swivelling their hips and rolling their arms – but it's not to everyone's liking. (Photo by Kim Kyung-Hoon/Reuters)

This picture taken on December 17, 2013 shows people taking photos of a pole dancer (R) practising after it snowed in Tianjin during a promotional event by members of China's national pole dancing team and students of the sport. China set up its first national pole dancing team in Tianjin in 2012 in order to compete in the World Pole Dancing Championships. (Photo by AFP Photo)

Fotos Pole Street Buenos Aires – Miss Pole Dance Argentina 2012. (Photo by Diego Castillo)

Regina Halmich and Sergiy Plyuta perform during the 'Let's Dance' TV show at Coloneum on March 23, 2011 in Cologne, Germany.

Dancers from the Yarrabah community perform during the Laura Aboriginal Dance Festival on June 18, 2011 in Laura, Australia. The Laura Aboriginal Dance Festival is a celebration of aboriginal dance and culture that takes place Biennially in Cape York Peninsula at the site of a traditional Bora ground that is sacred to the aboriginal community and surrounded by some of the oldest rock art in the world. Over 5000 visitors attend the festival, offering a unique insight into the community and providing an opportunity to spread cultural traditions to new generations. The festival takes place June 17-19. (Photo by Mark Kolbe/Getty Images for Tourism Queensland)

Coloured X-ray of a barn owl. A physicist has used X-ray to create an extraordinary collection of artwork. Arie van't Riets pictures reveal birds, fish, monkeys and flowers in an incredible new light. The 66-year-old, from Bathmen in the Netherlands, began X-raying flowers as a means to teach radiographers and physicians how the machine worked. But after adding a bit of colour to the pictures, the retired medical physicist realised the potential for an exciting new collection of art. (Photo by Arie van't Riet/Barcroft Media)

The X-47B prototype on Tuesday flew off an aircraft carrier and into the history books. Today's achievement, the first-ever catapult launch of an unmanned aircraft from the flight deck of a carrier, promises to open up a new chapter in the annals of naval aviation. Photo: An X-47B pilot-less drone combat aircraft is launched for the first time off an aircraft carrier, the USS George H. W. Bush, in the Atlantic Ocean off the coast of Virginia, May 14, 2013. The U.S. Navy made aviation history on Tuesday by catapulting an unmanned jet off an aircraft carrier for the first time, testing a long-range, stealthy, bat-winged plane that represents a jump forward in drone technology. (Photo by Jason Reed/Reuters)