First stop was Dover Castle. I love visiting old castles (blog posts on visits to Leeds Castle in Kent here , Corfe Castle in Dorset here and Edinburgh castle here) for the atmosphere, history and because of the opportunities for the kids to explore without breaking things (just about).
The castle wasn't as big as some of the others, but probably made up for it in two ways - the exhibits inside of everyday medieval castle life and all of the nooks and stairways you can wander around.
This was the view from the top of the castle. The stairs made my legs hurt and had me out of breath (think scary, spiral, stone stairs that are too narrow on one side) but were worth the effort.