- Deep Sea World, Scotland's National Aquarium which has a spectacular 112m (IIRC) underwater tunnel - the highlight of which was when my daughter realised a shark was swimming over her head!
- Edinburgh Castle, a very splendid castle with some fascinating regimental museums as well
- Falkland Palace & Garden
The surface guardhouse was built to resemble a Scottish farmhouse and gives no clue to the extensive bunker beneath it:
And it certainly is extensive! This (blurry :( ) pic shows a plan of the top floor of the bunker (The orange parts are still restricted and cannot be accessed by the public), and there are another 3 below it! (Although the bottom 2 were sealed off before the bunker was sold)
For anyone interested in modern warfare or post-apocalyptic gaming, I would heartily recommend a visit to this place. Along with seeing it, you also get a wealth of information about the capabilities of a place like this - e.g. the air-conditioning system can change ALL of the air in the bunker 14 times every 15 minutes!!, the 3m concrete shell surrounding the bunker has tungsten rods every 30cm to protect the structure from a nuclear blast's EMP, etc ...
If you get the chance - go there and be sure to get the audio guide if you do!
edited: for Mathyoo's benefit, here's a pic of a shark that I took while in the underwater tunnel at Deep Sea World: