natalia zaremba did not like the measure of it.ussians had killed her husband, the father of her two boys. was this risk foolish? >> why do you put them on this dam? >> we put them on this dam because we want them to confront discomfort. we want them to confront their fears. >> reporter: nathan schmidt cofounded the mountain seed foundation charity. we met in the 700-square-mile park, where the dam, finished after world war ii, is a tourist attraction for rock climbers. >> what makes this safe, in your view? >> first off, we have professional mountain guides. the second thing is all the equipment that we have, we -- they train throughout the week on it. they know how to use the equipment. and then particularly the little children, they are also short roped in to a guide. so, there's multiple layers of security for them. >> reporter: and so, with all that security, the challenge was not so much under their feet as under their skin. >> and here we go. >> reporter: myroslav kupchenkov, who told us his late father never went back, alwa