Altan, one of the students I tutor, told me about International Baccalaureate schools. One of the high schools he is applying to, Stuart Hall-San Francisco, is a Sacred Heart school and an IB school. Here are some impressive links:
https://www.sacredheartusc.education/#welcome
www.ibo.org/
https://www.sacredheartusc.education/#welcome
www.ibo.org/