You are in the scrublands of Mongolia, 25 million years ago.

The air in the Oligocene woodland was thick, smelling of crushed leaves and damp earth. You were crouched behind a dense thicket of fern-like foliage, trying to remain unseen, when the ground began to vibrate. It wasn’t a tremor; it was a rhythmic, heavy thump-thump that I felt in my chest cavity before you heard it clearly over the forest chorus.

Then, the trees ahead parted.

You didn't immediately see a face; you saw legs—mammoth, pillar-like legs, gray and scarred, that seemed to connect directly with the sky. You looked up, rising slowly from your hiding spot, dwarfed beyond comprehension.

It was a Paraceratherium. The hornless, sloping skull hovered nearly twenty feet above the ground, its prehensile upper lip tearing away a massive branch as if it were a twig.

The giant paused, its long, muscular neck turning slightly, and an eye the size of your head shifted toward you. It looked intensely indifferent, a calm titan of its time. The sheer scale of the creature was paralyzing; it made an elephant look like a mere calf. It huffed, a sound like a rushing gust of wind, exhaling a hot, moist mist that smelled of masticated greenery.