Hi, I'm an American traveling from London to Paris on the Eurostar. I've never traveled on any sort of quote on quote International train and I have no idea how this works. My main problem is I'm not sure what I need to bring in terms of passport and tickets. Of course I know I need those two things but will I be needing anything extra besides that? Also how does the Eurostar Customs work? Will I just have to go through a normal security line and normal Customs on my way to and from London and Paris?