Here’s an enviable spot to camp, midway between glorious Glacier and Yellowstone National Parks. But don’t hurry away until you’ve had a chance to explore Butte. It’s easy: Just hop onto “Old Number One,” the trolley car that boards next door at the Chamber of Commerce. Berkeley Pit is an engineering marvel, the largest truck-operated open-pit copper mine in America. Mansions of old-time mining barons cluster in Butte neighborhoods.