Machu Picchu is a mesmerizing, ancient Incan city tucked away in the mountains of Peru, but it is rapidly being worn down by the thousands of feet treading across its stones. Glacier National Park is a destination long known for the stunning beauty of its ice floes, but in our lifetimes it will have no glaciers due to global warming. In the biobays of Puerto Rico swimmers can float in a sea shimmering with bioluminescent life, but sediment being churned up by development is killing the dinoflagellates that produce the eerie and beautiful glow. And in the Congo Basin of Africa, where great apes roam freely in lush, verdant rainforests, logging is quickly destroying the vast life-giving canopies. These places-along with many others across the globe-are changing as we speak due to global warming, environmental degradation, overuse, and natural causes.