Under the National Security Act, South Koreans can be sentenced for everything from re-tweeting North Korea's official Twitter account to reading northern propaganda.
Cities are dynamos of the global economy. Encouraging new ideas on transportation, food, housing, and jobs can make them even more vibrant.
The Kaesong Industrial Complex, shuttered earlier this year, is one of the only areas of cooperation between rivals North and South Korea.
Investigators are interviewing the flight's pilots and crew to help determine the cause of the Asiana crash at San Francisco International Airport on Saturday. Here are several factors under scrutiny.