The Imperial War Museum is in London.  It has a number of different exhibitions inside, some of which I was too young to go in (Dad said they were to scary for me), but the ones I saw were good.  There were Children's activities on the day we visited, but I didn't do any.

Site : Smaller than I expected.  Lots of floors.

Contents : Great !

Toilets : Can't remember

Cafe : Not enough seats

Shop : Good, but didn't get much.  Dad got a Children at War book.

Crowds : Not too bad, though there was a bit of a queue for the monorail and cafe.

Best Bit : World War 1 trench scenes

Worst Bit : Cafe - they didn't have anything I liked and it was hard to find somewhere to sit down.

Dad's Thoughts : I loved the Tanks !  Some areas are too disturbing for young children - though these are clearly sign posted.

The Main Hall (from front)

World War 1 scene
 

Main Hall (from back)