Every visit to Colorado should include a road trip. And every Colorado road trip should include the highest continuous mountain road in the United States: Trail Ridge (Highway 34), in Rocky Mountain National Park, is a 48-mile journey through some of the state’s most diverse ecosystems. But it just scratches the surface of RMNP’s glacier-carved valleys, 150 alpine lakes, and 450 miles of waterways (including the Colorado River). More than 60 peaks rise over 12,000 feet, and Longs Peak hits 14,259. The animals—elk, moose, pika, marmot, ptarmigan, and bighorn sheep—will keep you on the edge of your seat. Begin in Estes Park, then wind up to scenic pull-offs like the Alpine Visitor Center. Pass the Continental Divide at Milner Pass, at 10,120 feet, where water to the east flows toward the Atlantic and waters west flow to the Pacific.