The laboratory tests and complex work involved in constructing the dam in the Lei Valley are described in detail to give an idea of the complexity of building the Lei Rhine dam. Among double-curved arch dams, this one has the widest crest in the world. The construction of the dam is punctuated by the long speeches and anecdotes of an elderly master builder.
| Actor | Role |
|---|---|
 Romolo ValliNarrator (voice) | Narrator (voice) |
| AAlfredo DantiNarrator (voice) | Narrator (voice) |