Definitely worth seeing. Take the free tour at th...

Definitely worth seeing. Take the free tour at the start with the Queen's Guard. Very informative and really makes the tour wonderful. Our guard was a riot. To see it all you need several hours. Make this a day trip to give yourself plenty of time to see everything. There are lots of stairs so bring your sensible shoes. We walked the Thames river path to get there from Westminster. There are also water shuttles (not cruise) rides very affordable that come every 15 minutes. We took it back. Very relaxing. It uses tap (debit/credit) cards but you must have one per person so I'm not sure how that works when traveling with children, I'm sure they have a solution so just ask at the desk.