United World Colleges or UW.
It's a global organization devoted to make education a force to achieve international/cultural understanding, peace and a sustainable future, amongst other things.
It consists of 13 colleges spread all over the 5 continents. All students come from different countries and have diverse backgrounds and are all on scholarships. For more info you can visit www.uwc.org.
For americans, www.uwc-usa.org
I personally went to one of these schools, Pearson College in BC, Canada. I applied through my national committee of Chile without any hopes really, only to find out later I had gotten a full scholarship to study at this school for 2 years. The program we did was the International Baccalaureate (IB) which is widely accepted around the world to apply for university.
I was just looking for a different educational experience and it ended up changing my life. It opened so many doors for me. Thanks to this experience I managed to get into a really good school in the states and it helps if you are anywhere in the world really, not only economically.
This is getting long, so what I wanna get to is that it's an amazing experience. So if you are between 16-19 or have completed 10-11 years of formal education then you can apply. Different countries have different application standards.
Find out more about your national committees and take a look at the website. It's definitely worth checking out. Spread the word since not too many people have heard of this.
Sorry its too long but if you are interested or have any questions just ask here or pm me.