Zion National Park's unique feature aptly named "The Subway".
This is an amazing geologic feature, maybe the most unique and impressive I've seen. Erosion has carved a beautiful curving structure that almost has to be seen to be believed. Although not a true "Subway", it does have a small opening in the top, but when you're standing there at certain angle, deep in the canyon, it certainly feel like a Subway.
The ice formations seen are formed by water trickling through the sandstone and finding an exit in the location from the rock itself. Interesting to think of how long a journey the H2O molecules might have taken through the rock to finally see the light of day in this particular location. I've heard in some places in the Zion NP area it takes thousands of year filtering through rock.
I have been to this place a few other times and have wanted to get back in the Winter. Our original plan was to drive back this day, but my wife hadn't been to this amazing place yet and showing her was just the excuse I needed to get the back-country permit and hike back. It's a strenuous hike in any season, but the icy conditions (and being out of shape from Winter hibernation) made it a visit we very much had to earn.FACEBOOK