This is undoubtedly one of the most popular trails in Rocky Mountain National Park. Many people who set foot on no other trail still hike this one, or at least attempt it. That's because it starts from the Alpine Visitor Center on Trail Ridge Road, a very crowded place during summer. The hike is tantalizingly short, but quite steep, and reaches 12,000 feet elevation, making it difficult if you're not in decent shape. It's all paved, and mostly just stairs from start to finish.