Best time to go
Go early in the day or outside the busiest summer weekends if you want more time at the audio points and displays. The underground temperature barely changes with the weather, making this a useful wet-day stop, but the approach and return path can be especially slippery after rain. Late afternoon gives the best light on the exterior buildings and mountain view; inside, expect a deliberately dark, atmospheric experience.
The attraction follows a longstanding seasonal pattern, with broad spring-to-autumn opening and more limited winter dates. Check the current opening pattern before making a special trip, and remember that the final underground admission is before closing.
