You are in the swamp forests of South America, 60 million years ago.

The jungle was overwhelmingly humid, a damp heat that clung to the skin. You were paddling a small dugout canoe along the edge of a slow-moving, chocolate-brown river in what is now northern Colombia.

Everything was silent, too quiet. The typical screeching of birds had stopped. Suddenly, something massive and long submerged ten feet away. It wasn't a log.

It was a muscle-bound creature, brownish-gray like the mud, with a width that dwarfed the canoe. The sheer length was impossible, extending far deeper into the water than you could see. The creature didn't break the surface fully—just a slow, deliberate glisten of scales. A Titanoboa, the undisputed ruler of this swamp, had passed…