bottles. all have to be the same high. it's a little different. what we're doing is using a metal frame instead of wood. also we are using beams. these are metal beams attached to columns and then when you put the metal frame, you just bend this over here and so it makes it really tight. >> they are really strong. >> this is a very safe construction. we actually comply with different rules internationally and we have the support of different engineers and architects. >> we've only been here four days so far but we already built a couple of the bottled walls that you see behind us. one of the great things is the partner that's here with me is locally trained builder from the himalayas and we talk about what will work in the himalaas and how we can change things. for instance, in guatemala, the climate is totally different. we're high altitude desert above