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.

Demi Rose attends Sixty6 Magazine – issue two launch party at Paper club on March 22, 2017 in London, England. (Photo by Splash News and Pictures)

Hospitality staff members laugh as they stand on Tiananmen Square before the closing ceremony of China's 19th Party Congress at the Great Hall of the People in Beijing, Tuesday, October 24, 2017. The ruling Communist Party on Tuesday formally lifted Xi Jinping's status to China's most powerful ruler in decades, setting the stage for the authoritarian leader to tighten his grip over the country while pursuing an increasingly muscular foreign policy and military expansion. (Photo by Mark Schiefelbein/AP Photo)

Morgan Miller carries her one-year-old daughter Mia Jennings in one arm as she shovels the stairs to her Springfield home with the other Sunday, January 13, 2019. Miller said she's learned how to do a lot of things while holding a baby in the last year. (Photo by Ted Schurter/The State Journal-Register via AP Photo)

A park ranger stands next to a nothern white female rhinoceros named Najin at Ol Pejeta Conservancy, some 290 kms north of the Kenyan capital, Nairobi, on January 27, 2015. Najin is one of only five members of the sub-species left on the planet, three of which reside at Ol Pejeta Conservancy. Conservationists and scientists met in Kenya this week to come up with a last ditch plan to save the northern white rhinoceros from extinction. (Photo by Tony Karumba/AFP Photo)

A twelve foot long giant hamster has surprised Londoners along the South Bank, Millennium Bridge and Clapham Common on May 26, 2016. A 4-metre pedal-powered mechanical model hamster, which has been created in the likeness of Jaffa the hamster, who is listed as one of the 10 oddest discoveries made by Kwik Fit technicians in customers’ cars. (Photo by Joe Pepler/Rex Features/Shutterstock)

A broken picture frame is left in the tsunami-hit Arahama area, three months and two days after the magnitude 9.0 earthquake and subsequent tsunami on June 13, 2011 in Sendai, Miyagi, Japan. Japanese government has been struggling to deal with the earthquake and tsunami as well as the troubled Fukushima Daiichi Nuclear Power Plant. The fear on outbreak of virus infectious disease are mounting due to the humid rainy season on the corner and delay of the clearing the debris. (Photo by Kiyoshi Ota/Getty Images)

In this Thursday, April 11, 2013 photo, North Korean female soldiers stand watch on the river bank of the North Korean town of Sinuiju, opposite to the Chinese border city of Dandong. (Photo by AP Photo)