There are so many aspects to our group traveling that will benefit your student way beyond their high school years:
Budgeting time and money
An appreciation of other geographical areas
Etiquette
History and culture
Perseverance (many of them wanted to quit the hike. They were glad they didn't)
Team work
Relationship building
Patience
Making decisions
Communication
Navigating a city
Tolerance
Sacrifice (Not having signals to their cell phones was shocking at first, but not missed once immersed in the activity at hand. This not only happened once, but many times throughout our trip.) 😉 A wonderful sight to see the group "unplugged" and really focused on something besides social media.
I am sure the list goes on. Feel free to add on to the list in the comment section!