well what would you consider interesting? Just wandering the streets of any of those cities was immensely fascinating for me. Just imagine any given city block there has perhaps seen more history that all of Canada.
We ate some really wierd crap like squid ink spaghetti and egg pizza, all downed with crappy but cheap and plentiful house wine ($5/L!). Drinking in England was especially interesting, found out the hard way that 1 pint = about 3 beers.
I found staying in B&Bs (i.e. rented rooms), albeit less comfortable, more rewarding than staying in hotels. Met some really friendly fellow travellers, which counterbalanced the relatively rude reception we recieved from the locals.
Things like wandering into a renaissance ceremony re-enactment, figuring out Italian bus schedules, or having an 11oclock dinner on a pitch black street next to a canal. Well, those can't really be described