As an Englishman, I was not taught much (if anything) about American history prior to WW1. As such, I have pretty limited knowledge about most of it, including the fight for independence and the Civil War.
Did any particular country try to assist the other at any point? During European conflicts, neutral nations would usually offer support either for the status quo or the rebels depending on which would be more politically expedient to them. With the US not being a superpower at the time and with them being so far away, was there very little European meddling here?
Also, I imagine most nations would have supported the Union, so was there any support for the confederacy at all outside of the US? I understand the US was one of the last countries to ban slavery
I've written on internationalist and the Civil War a few times, I would point to this collection of answers which might be of interest to you for some aspects of this.