The 39 Clues series is pure pleasure reading 😎 It’s an adventure series targeted at pre-teens so it’s really easy and goofy. What I like is that the kids travel all over the world ( Boston, Paris, Vienna, Venice, Korea, Egypt, Russia, Australia, and more) and they deal with important historical figures ( Ben Franklin, Mozart, Romanovs, Pharoahs, etc )
I’d never heard of The Motherland Calls statue in Volgograd before. Wow! This is in book 5.