And looking at tunneling technology, it turns out that in order to make a tunnel, you have to -- In order to seal against the water table, you've got to typically design a tunnel wall to be good to about five or six atmospheres.
Pokud se podíváte na technologii ražby, ukazuje se, že abyste vyhloubili tunel, musíte … abyste ho utěsnili kvůli tlaku vody, je typicky potřeba navrhovat zdi tunelu tak, aby odolaly tlaku okolo pěti, šesti atmosfér.