Mauna Kea Observatories
This was one of my favorite sites in Hawaii. We almost missed it. We only wish we could've stayed to see the stars. It looks a bit futuristic and science fiction-like. If you go up, take a 45 minute break to get acclimated to the climate and pressure. This is suppose to be one of the tallest mountains in the world if you include sea level, 14,000 feet high. This is as close to the clouds as you can get without the window seat in an airplane.
For more photos, click here.