Developed by the Air Force to help its officers acclimate overseas, this exhaustively researched app focuses on etiquette, traditions and politics, primarily those in Africa, the Middle East, Southeast Asia and Eastern Europe. Categories like Personal Space and Eye Contact, Conversational Topics, Natural Hazards and Dining Customs come in handy for civilians too. The deep dives cover everything from how to shake hands with a Bulgarian, why Indonesians typically eat with their right hands, which gestures are considered impolite in the Congo (word to the wise: avoid the...