Waura Indians wrestle during this year's “quarup”, a ritual held over several days to honour in death a person of great importance to them, in Xingu National Park, Mato Grosso State, Brazil August 25, 2013. (Photo by Ueslei Marcelino/Reuters)

Porcelain Black performs during the ' I Am Still Music' Tour at the Wells Fargo Center on March 26, 2011 in Philadelphia, Pennsylvania

Spectators await the start of a cinema screening at a Kinostar De Lux Multiplex in the Moscow suburb of Khimki, December 7, 2014. Furniture retailer IKEA has converted one of the cinema halls, completely replacing standard seats with their furniture, according to local media. There are 17 double beds fitted in the hall, which was renamed to “It wakes love”. (Photo by Sergei Karpukhin/Reuters)

The Flying Bull's P-38 Lockheed Lightning N25Y / 13 – Red Bull – Flying Legends Airshow 2012 Duxford (Photo by Rob Lovesey)

Actors Justin Timberlake (L) and Mila Kunis present an award onstage during the 2011 MTV Movie Awards at Universal Studios' Gibson Amphitheatre on June 5, 2011 in Universal City, California. (Photo by Kevin Winter/Getty Images)

Selena Gomez performs at the MTV Movie Awards. (Photo by Jordan Strauss/Invision for MTV)

Most pet cats will become timid or defensive when outdoors, but not Millie – after being adopted by her mountain-climbing owner Craig Armstrong, Millie has become a feline hiking and mountain-climbing legend.