10 Natural Wonders To See Before They Disappear

You've heard the grim timelines: if warming continues, the Great Barrier Reef will be bleached by 2030; glaciers in the Swiss Alps, on Mt. Kilimanjaro, and in Glacier National Park will disappear in under 40 years; and Arctic ice melt will send polar bears into extinction. The immediacy of these timelines prompts flocks of curious eco-tourists to travel to environmentally fragile areas.

Here are 10 areas under threat - some lesser known than others - that can still be visited responsibly.