i want to go right now to ed sorens sorensen. he is a cave dive instructor. he teaches people how to dive in caves safely. ed, you are one of the perfect people to talk about the challenges here. i've tried to describe them, marrying with the pictures, put mig word putting my words to what these boys are facing. >> that's the thing. with every cave scenario, every cave is different. that's why it needs to be left to the on-scene personnel. they know what the conditions are, the most and not being an armchair quarterback. in this particular instance, they have a lot of obstacles. usually, you have one, two or three. they have all of the worst of the worst. they have the tight restrictions, which are extremely stressful for an experienced cave diver, let alone, if they're not swimmers, they've spent little time submerged in the water. that's an extremely stressful situation. zero visibility, extremely stressful. so, they're not going to know what to do. they're having to use equipment they've never used. so, it's just fantastic. nothing short of a miracle that t