Daniel España and Lucas Marmol, both 19 and business students at the IE University in Segovia, Spain, recently returned there from a two-month sojourn to the low-income neighborhoods of Nairobi, Kenya where they taught Spanish, coached sports and explored entrepreneurship. Knowledge@Wharton High School spoke with them about their experience and the professional, personal and human impact of working in a beautiful, yet troubled, region of the world.…