You are in the forests of North America, 2 million years ago.

The air in the subtropical valley was thick, smelling of wet earth and crushed vegetation. You froze as a massive shadow detached itself from the treeline.

It was an Eremotherium—a giant ground sloth—and it was easily as tall as the tree-house-sized canopy you were standing near. It moved with a slow, heavy shuffling, bringing with it an aura of absolute invincibility. Its fur was patchy, coated in mud, and its long, curved claws tore easily into a large tree branch, snapping it like a toothpick to reach the tender leaves.

You watched, holding your breath, as it decided to stand on its hind legs to reach higher, tower over you, its massive claws swaying gently, each one long enough to deal a killing blow to any saber-toothed cat that might have dared to approach. It wasn't looking at you; I was nothing but an insect to it. It possessed a quiet, gargantuan power.