>How do you think LIDAR tech is going to upend our understanding of history?

It isn't, because that isn't how historical study works. Everything you discover using any method is added to what you already know. The most it does is upend people, who either have long-held beliefs about a certain aspect of history, or are crackpots who seize on it as proof their personal (and otherwise unsupported) brand of lunacy is correct and everyone else is wrong. Fruit loops, like Hancock for instance, always talk about totally upsetting established history, because they don't have a single bit of proof for what they believe, and they desperately want some evidence, any evidence, for what has become their individual religion, if not brand.

>Maybe give us a better perspective on those "barbarians" that invaded Rome

If you're talking about Alaric and the Goths, his name was Flavius Alaricus, and he was a Roman citizen. We have plenty of evidence showing Rome didn't 'fall' as commonly thought, and the pop history narratives around it are comprehensively wrong, based on writings that are hundreds of years out of date.

>or possibly cities that were erased before history.

LIDAR is great for finding sites. It's not going to find something that isn't there. This thread shows what LIDAR surveys can find, as an example. It's a fantastic method, relatively fast, surprisingly accurate. But like any method, it has to be used in conjunction with many others, over the course of years, to do patient, careful research to establish new evidence, and add that evidence to what has already been accumulated.