Walking up the cobblestone windy passage at the end of The Royal Mile which is the heart of the city, you will pass bagpipe players, harpists and the scene would not be complete without a visit from Braveheart. The Royal Mile is a Quaint part of Edinburgh where most tours will start and finish. My advice is if walking in the rain on the cobblestones be very careful- I had a nasty fall not realising just how slippery they got! Falling on the cobblestone is one thing but in the cracks not so great! I say that incase you should be travelling with someone who is relying on a walking stick or has any issues with their legs or walking in general.
I will be honest and say I do not know much about Edinburgh Castle. It does hold some important History. I am going to quote the website here and say the following;
In 1314 it was retaken from the English by Thomas Randolph, Nephew of Robert the Bruce. Queen Margaret died at the Castle in 1093 and Queen Mary of Scots gave birth to James VI in 1566.
Charles Edward Stuart- Bonnie Prince Charlie captured Edinburgh but couldn't take the Castle during 1745- 1746 Jacobite rising. From 1600's onwards the Castle was a military base. and also held prisoners of war.
The Castle is a key element of the Edinburgh World Heritage site. Some magnificent views of the city (such as first image) can be seen from the Castle. There is also a fair amount to enjoy without paying entry.