The photo above depicts a journey through the ice caves below the Mendenhall Glacier in Juneau, Alaska. The glacier's retreat and rapid melting has caused these caves to form (and collapse) over the past few hundred years. Touring them is an activity not for unadventurous types -- reaching the caves typically involves an arduous hike, sometimes over the glacier itself.

Warm weather has expedited the glacier's retreat and hundreds of feet of ice disappear each year. Barring a shift in weather patterns that would bring more snowfall and less melting, the Mendenhall Glacier will disappear in the next few centuries, so book your tickets today. Be sure to grab some dumplings while you're in town.

Photo credit: Andrew Russell / Flickr

For more photos and info, check out this feature in The Huffington Post

Also, read this article about the ancient forest frozen beneath the glacier at Live Science

Finally, click here for time-lapse photos of Mendenhall Glacier's dramatic retreat