Another week, another challenge. I’ve climbed quite a few mountains over the years, but there was something special about the time I spent on top of Gibraltar. It’s all about scale; the bustling tourist town seems huge at first, but you realize how small it is from up above. You’re just high enough to see the curvature of the planet. Gibraltar is one of those rare places that make you acutely aware of your exact position on the Earth. It’s at the southernmost tip of Europe, and you can just make out Africa across the water on a clear day. It may not have been the highest peak I’ve ever seen, but it was one of the most memorable.