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.

Smoke rises from a replica of a T-Rex after it burst into flames at the Royal Gorge Dinosaur Experience in Canon City, Colorado, U.S. in this picture obtained from social media March 22, 2018. (Photo by Reuters/Royal Gorge Dinosaur Experience)

This photo shows sunset in Eagle, Colo., Sunday, November 3, 2019. Daylight saving time ended, making sunset around 5 p.m. this time of year in Colorado. (Photo by Chris Dillmann/Vail Daily via AP Photo)

A mushroom cloud dwarfs a row of skyscrapers in what looks like a devastating nuclear bomb detonation. But thankfully this is just a spectacular weather-front blasting in from the tempestuous Rocky Mountains near Denver, Colorado, USA. The unbelievable shot is just one of many of the city's skyline taken by photographer Greg Thow. The 49-year-old has also captured equally stunning shots of lightning blasts and arching rainbows – all from the comfort of his balcony. (Photo by Greg Thow/Barcroft Media)

“The Wild Animal Sanctuary is a U.S. organization that specializes in rescuing and caring for large predators which are being ill-treated, for which their owners can no longer care, or which might otherwise be euthanized. Created in 1980, The Wild Animal Sanctuary is situated on 720 acres (291 ha) of grassland near Keenesburg, Colorado North of Denver, and has helped over 1,000 animals since it first opened. As of 2010, it was home to over 290 animals”. – Wikipedia

Photo: Rescued brown and black bears feed at The Wild Animal Sanctuary on October 20, 2011 in Keenesburg, Colorado. (Photo by John Moore/Getty Images)

Emma White, of Team Cyclocrossworld, hits the dirt hard during the USA Cycling Cyclo-cross National Championship Elite Women's race at the Valmont Bike Park in Boulder, Colorado, on January 12, 2014. (Photo by Jeremy Papasso/The Daily Camera)

A woman walks by a bank's currency advertisement board in Seoul, South Korea, Friday, September 23, 2022. Asian stocks fell for a third day Friday after more rate hikes by the Federal Reserve and other central banks to control persistent inflation spurred fears of a possible global recession. (Photo by Ahn Young-joon/AP Photo)

A Russian police officer detains a teenager during rally protesting retirement age hikes in St. Petersburg, Russia, Sunday, September 9, 2018. A government plan to increase the age for collecting state pensions brought protests across Russia's 11 time zones on Sunday even though the opposition leader who called them was in jail. Nearly 300 people were reported arrested. (Photo by Roman Pimenov/Interpress photo via AP Photo)