[Julius] Caesar was the first Roman to build a military bridge across the Rhine and cause the Germans on the farther bank heavy losses. He also invaded Britain, a hitherto unknown country, and defeated the natives, from whom he exacted a large sum of money as well as hostages for future good behaviour.
I remember seeing a documentary piece on that bridge Julius built over the Rhine. At the time it was considered a technological wonder (and, for all I know, such a bridge today would still be a wonder) because it was built over the Rhine in order to accommodate the Roman army.
Not just a wagon or two, but an entire army of bad-ass Romans eager to kick some German butt.
Before this bridge was built the Germanic tribes remained largely unmolested by the Romans because of the natural defensive line the Rhine provided, giving them a sense of security on their side of the river. But Julius Caesar said, Screw that. If I'm going to show these Germans who's really the boss, I'm going to need to get serious and build me a REAL bridge, one that will leave them slack-jawed while I march into their county like I owned the place.
And build it, he did. He crossed the bridge and kicked a few things down. And then, to show those barbarians that the Romans were hardcore enough to do pretty much whatever they wanted whenever they wanted, he marched his army back across the bridge and dismantled it behind him.
And then a couple of years later, he did it again. Just as a reminder.
His strategy largely paid off. It made the Germanic tribes rethink how they handled the Romans, perhaps convincing them that if Caesar was batty enough to build such infrastructure only to immediately tear it down (twice!) just to show that he could, then perhaps he was just batty enough to do anything he wanted to them.
And then, he conquered Britain. In a manner of speaking.
All I need is a bridge long enough. --Caesar