You are in the woodlands of North America, 110 million years ago.

The air in the early Cretaceous forest was thick, humid, and smelled of wet earth and ancient ferns. You froze behind the trunk of a towering conifer, your breath hitching as a low, shuffling sound broke the silence. Emerging from the undergrowth was a creature that looked less like a living animal and more like a walking, pine-cone-shaped fortress—a Borealopelta.

It was magnificent, roughly 18 feet long and covered in intricate, reddish-brown armor plates. The spines jutting from its shoulders were larger than your forearm, gleaming with dampness. As it stopped to graze, you saw the countershading—dark on top, lighter on its belly—a testament to the camouflage that helped it hide in this dappled light.

It ignored you entirely, its attention fixed on a patch of ferns, its beak shearing through the foliage. For a few, terrifyingly silent minutes, you are invisible to a 3,000-pound living statue, a silent observer of a lost world.