I stumbled across r/AskHistorians a little while ago and it is a fantastic group. It is heavily moderated and only answers which meet their standards are accepted - as in by a historian or someone with relevant knowledge who can cite references in back up. (Proper academic references, not Wikipedia.) You can ask any question that has been puzzling you and you may (or may not) get an in depth answer. People are asking all sorts of questions such as "Jesus was a carpenter - what sort of things would he have made?" it is fascinating reading even if you don't have a question to ask.