![A gang of puddlers pack wet concrete into the base of Hoover Dam as an eight cubic-yard bucket spews out 16 tons of concrete at a time. The dam is a concrete gravity-arch which is designed to resist overturning, sliding and crushing at the toe. It's mass inspires safety and stability upon first glance.](http://media.lasvegassun.com/media/img/photos/2008/04/22/scaled.1334_hoover_dam005_t653.jpg?214bc4f9d9bd7c08c7d0f6599bb3328710e01e7b)
UNLV Special Collections
A gang of puddlers pack wet concrete into the base of Hoover Dam as an eight cubic-yard bucket spews out 16 tons of concrete at a time. The dam is a concrete gravity-arch which is designed to resist overturning, sliding and crushing at the toe. It's mass inspires safety and stability upon first glance.