>> pelley: 50 years ago president johnson signed the wilderness act to preserve millions of acres of america's natural beauty. now, with that same goal in mind, google has used modern technology to map our ancient lands. here's chip reid. >> reporter: they tower 300 feet into the sky, the length of a football field. and at almost 2,000 years old, northern california's old-growth redwoods are some of the tallest and oldest living things on earth. ben blom is the land manager here at the headwaters forest preserve. there's a blue stripe on that enormous tree behind you. what exactly does that mean? >> that's a mark to cut. so that tree was going to be cut down until headwaters was protected and acquired by the federal government and the state in 1999. >> reporter: that beautiful tree was going to be cut down. >> that and every other every one in this stand.