Take an Incredible Spherical Panoramic Tour prepared for the Observatory by Carel Struycken, Star Trek's Mr. Homn and Adams Family member Lurch.
Click here to load the tour. It will take you to 20 different spots on the mountain, including spaces not open to visitors. Use the built-in navigation bar to select your vantage point, zoom in and out, switch to full screen, and turn auto-rotation on/off. Then click and drag your cursor go left-right and up-down. There is no direction in which you cannot look!
For more about Mr. Struycken's amazing spherical panoramas, click here.