Leituras

For these reasons Caesar had determined to cross the Rhine, but a crossing by means of boats seemed to him both too risky and beneath his dignity as a Roman commander. Therefore, although the construction of a bridge presented very great dificulties on account of the breadth, depth, and swiftness of the stream, he decided that he must either attempt it or give up the idea of crossing.
[...]
The pairs of piles being thus held apart, and each pair individually strengthened by a diagonal tie between the two piles, the whole structure was so rigid that, in accordance with the laws of physics(1), the greater the force of the current, the more tightly were the piles held in position.

- Júlio César, "A Conquista da Gália"

César recolheu a madeira, construiu a ponte e atravessou o Reno com o seu exército em 10 dias.

(1) É notável como já usava esta expressão.