Although it measures some 10 miles long, one mile wide, and more than 3,500 feet deep, it's not only the size that's impressive about Waimea Canyon (the largest in the Pacific)-it's also the colors! The deeply scarred canyon walls, carved from rivers that pour down from Mt. Waialeale's wet summit, shimmer and shine in the sunlight like a palette of deep-hued jewels. Emerald-green folds and rugged dark cliffs plunge into the rust-colored rivers below. On clear days (mornings are the best times), you may see waterfalls and rainbows against the eons-old volcanic rock.