National History Day Help

Hey all. My Mother-In-Law(no Pics) is a 5-6 grade teacher in a nice school. Every year, they participate heavily in National History Day. She always has students make it to the Wisconsin State finals, and she has had a few go to the Nationals. Every year, there is a new theme, and each student needs to make a presentation on a subject that that falls into that category. This year, the theme is Exploration, Encounter, and Exchange. I was hoping to get some subjects from the OG that would be interesting and new for the judges. I know there will be a bunch of Lewis and Clark, and Marco Polo kind of stuff. My Mother-in-Law liked my suggestion of UFO encounters. It is best to have a lot of research available to them. I also suggested Operation Paperclip. Thanks bros.