As long as we have obsessed over the height of coast redwoods and giant sequoias, we’ve also pondered over their age. After all, these trees live on a timeline that extends hundreds, even thousands, of years longer than ours. And we’ve all been taught that the best way to learn the age of a tree is to cut it down and count tree rings, which unfortunately kills the tree. But is that the only way?

If you go online and look for historical photos of redwoods, you’ll find lots of photos of people driving their cars through tunnels that have been cut into the trees. And you might ask yourself, how did this become a thing? Who wants to drive their car through a tree? Maybe you’ve driven a car through a redwood. In this first episode of This Is Big, we take a deep dive into this strange phenomenon and learn how it’s connected to the entire culture we’ve built around these magnificent forests.