So the stories are great but Topolski’s painting, it must be said, is rather hard work. As an illustrator in ink he was a genius — the many reproductions, printed alongside well-written texts on the wall, demonstrate that — but he paints in an excessively loose Expressionist style that many will find tiring. There are many hidden treats in this historically significant monument, which tells the story of the 20th century as you’ve never been told it before but you may need a guided tour to get the most from it.