I was pretty startled to hear the news about the falling of Wall Arch at Arches National Park in Utah. Here's the National Park Service article. We made a trip out there two years ago, and that particular arch was one I remember well because of its proximity to the hiking trail. A stone wall blocked one side and the Wall Arch spanned along the opposite wall with the trail sandwiched between. The structure seemed very delicate at the time, but I got that same impression with most of the arches we saw there. It was a humbling feeling knowing those stones could topple on our heads at any moment.
I'm glad we took so many pictures.
(Arches National Park: Wall Arch 14 June 2006)