Greetings.
Some friends of mine are traveling on a cruise around the British Isles - which I believe will include a couple days in Edinburgh. This will be their first visit to Scotland. Are there any "must sees" they should try to do? I know they're going to the Tattoo and will be wandering up/down the Royal Mile - so anything not too far from there (time or distance, depending) would be nice for them.
Thanks much!
Rob