Yellowstone is home to over 10,000 hydrothermal ... Towering monoliths like El Capitan and Half Dome are not just sights to behold but also meccas for rock climbers worldwide.

And it's all in the US's most accessible national park. While you're car-dependent at Yellowstone, there's a free public shuttle throughout Yosemite, and train and bus connections to major Cali cities ...