Largest Cave

I just stumbled upon this National Geographic article of a cave in Vietnam. I've never seen or heard of such an incredible cave before! Apparently it is the largest cavern in the world (not longest but biggest) at 2.5 miles long, a sustained 300' wide and 600' high. Don't miss the pictures - they're unbelievable! Many of them have people in them, but you don't always see them at first because they look like ants in the picture!

Update: National Geographic has posted a video in which the photographer narrates and gives a presentation about finding and exploring this cave.