This is not some canned tour, with a guide who recites a script. No, it is a laid back, freewheeling, conversational experience, with guide who knows the park inside out. Its geology and geological history, its flora, its fauna, its climate, and how climate change is impacting the park's ecosystem. He also puts the park in the context in US history, culture, and economy. In conclusion, it was a valuable experience, with a knowledgeable and congenial guide.