I sat in a session a few weeks ago where some long term missionaries talked to a group of 8th graders about their ministry in Nepal. No personal details or pictures are in this post on purpose - Nepal is considered a 'closed' country.
What they shared was really interesting but I was even more fascinated with the significant global concepts that they touched upon. Ideas like: unreached people groups, church planting, population density, the caste system, tribal social networks, economic roles, THUMB [tribal hindu unreligious muslim buddhist], The Jesus Film, Buddhist prayer flags, oral versus written cultures, and churches planted to reach the unreached. They didn't dive into any of these in great detail, because certainly each one could almost be its own class. But like I've said before, middle schoolers can understand these ideas. It's our responsibility to intentionally expose them to these ideas.
If you work with middle school students, they already know a ton about the world. Maybe it's time for you to give that knowledge a catalytic filter.
PS - I heard about Nepal twice that week. But that doesn't mean I'm moving there.
Related: Middle School Missionaries