The bright October sun beams down on the rapid known as Lava Falls as though it were focused through a celestial magnifying glass. High above, the walls of the Grand Canyon rise nearly 5,000 feet, revealing 1.7 billion years of geologic history, from the pink Kaibab limestone down to the black Vishnu Schist. Each layer reveals another chapter of the earth's story. Rough, rocky stripes resemble a growth chart for the planet, the kind your parents likely marked on the kitchen wall or the doorway to your bedroom.
But for now, as I peer down from a bluff dotted with spiky yuccas and gnarled tamarisk bushes in search of a safe way through the boiling rapid, the past feels inconsequential. The thunder of the Colorado River, which drops a dramatic 13 feet at Lava Falls, rings in my ears. The exploding waves offer confirmation that we are set to descend one of the toughest stretches of whitewater in North America.