Foreign exchange - this one has a fall deadline. I think two of our students have done this
https://exchanges.state.gov/us/program/nsliy
Greenland 11th grade US citizen or PR https://dickey.dartmouth.edu/jsep/application
Antartica with Chilean students, most be proficient in Spanish 11th grade https://dickey.dartmouth.edu/environment/programs/joint-antarctic-school-expedition
I think these are free