India

Between my first and second years of med school, we had a 'summer break,' which was actually eight weeks of time in which we were supposed to go do something useful. Almost everyone fled the country.
I went to India with a group called the Himalayan Health Exchange. They are an independent group, with a core of dedicated American and Indian physicians who make multiple tours each year of the extremely remote areas on the border of India and Tibet to provide the only health care the people there ever get.
They take medical, dentist, and nursing students, as well as pretty much anyone interested in volunteering to help out in the camp or pharmacy.
We landed in New Dehli (I came by way of Singapore), then drove up into the Himalayan foothills to the last big city, Shimla, before heading out into true back country. We stopped for clinics and camps in the villages of Bhava, Sangla, Nako, Tabo, Kibbur, and Manali, and also visited the monasteries of Ki, Choling, and Dhankur along the way.
I learned a lot... mostly that people are people, no matter where they live, and mostly just want to live peaceful and healthy lives with their loved ones. They were universally grateful and generous people despite having next to nothing. In a time when, like most med students, I was wondering what the hell I was doing... this trip made it clear in my head that I was doing the right thing with my life.
I also learned that dogs are dogs and will listen to me despite not understanding English, and that Himalayan wild strawberries are the same as South Dakota ones, and do not give you rabies.