Having just lead a workshop in Arches National Park last December, I’m particularly saddened to hear that Wall Arch collapsed last week. At 33 feet tall and 71 feet across, Wall arch was the 12th largest in the park and took millions of years to form. When humans first inhabited the park 10,000 years ago they gazed upon the same, albeit slightly younger, arch.
As a side note, Balancing Rock (pictured below) is likely to collapse within the next 75 years. 
This is kind of a nice reminder that, no matter how “frozen in time” any natural formations are, they are part of a timeline far, far longer than our own lives, and are constantly evolving. Although initially saddened by this loss, I feel glad to be alive and to be able to see the things that are here during my own short sliver of a larger timeline. More importantly, it makes me want to get out there and see even more while I’m here.