An interesting account of things about the Tower of London.
Arranged in part thematically. The menagerie, with such details as how a polar bear was allowed to fish in the Thames when the budget for its meals was not enough, and how it was ended because Wellington thought of it as a military outpost, so a menagerie was inappropriate. Its time as a mint, with a lot on Sir Isaac Newton. Brushes on the ghosts, discusses escapes.
Most, of course, revolves about its prisoners, how they got there, how they ended up, whether they were executed on the grounds. Which is not, of course, light reading