Lots of places. Students have been to France, Kenya, Germany, Belgium, Canada, Ecuador, Scotland, England, Mexico, Wales, Congo, and the newly independent states of Russia. New sites are always under development. If you are already planning international travel, you may be able to get credit for the experience. A Coordinator can help you set up a program that meets your goals.
Some work is paid and some has special requirements.
In addition to tuition and travel expenses, there is a program fee. The details depend upon the specific arrangements.