 You've all heard about fracking, and you can do fracking in different contexts. It's at a really fundamental level. You just pump fluid down, and it creates permeability. The rocks, more often than not, where you're looking for the oil, have porosity. In other words, there's oil sitting there, but those pores are not interconnected. And that connection between pores is permeability. And so what the fracking does is it creates permeability, creates cracks between the pores and connects them up and allows the oil to flow out of what you might call a tight reservoir, one where if you drill down into it, even though there's oil there, the oil couldn't flow. So this just opened up a vast new areas of oil resources. And this happened in the latest part of the 20th century, early part of the 21st century. And oh my, it turned America from being a significant oil importer. Within the space of five years, they were poised to start exporting oil again, which is just amazing. We're talking about vast quantities of oil. The way this is done is you end up setting up these injection wells for the extraction in a row across a basin. And the basin may be 500 kilometers wide. So you'd have literally hundreds of platforms across the basin to extract the oil. And unlike traditional oil fields that might flow normally for tens of years, these oil production wells have very, very short production timelines, say just months. So what they do is they just will set up both an injection well and an extraction well on each one of these platforms and have them all in a row. And then month by month just move forward and just march across these basins, tens of kilometers at a time. And even though the oil in that area is used up relatively quickly, the amount of oil they're extracting collectively is an enormous amount. And so that too put downward pressure on the price of oil. And so we saw that happen in the early part of the 20th century. And so each time we've had one of these big technological breakthroughs, it's opened up new reservoirs of oil to extract and pushed the time horizon for running out of oil deeper into the future. To the point where now we're looking at actually stopping the use of oil way before we run out of oil. And so we'll talk about that next.