Welcome to high-country heaven. Jagged Rocky Mountain summits, emerald alpine lakes, and wildflower-filled meadows invite endless hiking, biking, rafting, and skiing. Set up camp near Rocky Mountain National Park for elk bugles at breakfast, tackle white-knuckle rapids on the Arkansas River, or soak in steamy hot springs after shredding powder in Aspen or Vail. In Colorado, the altitude is high and the adventure even higher.