Busan or Pusan? The name is spelled both ways on signs around the city. Before arriving, I'd have bet that the official name was Pusan, but I would have been wrong. In 2000, a new method of transliterating Korean was implemented and the name changed overnight to "Busan". The Korean character ㅂ represents both "b" and "p" (which, when you think about it, are nearly the same letter anyway). For the city's residents, there's no change at all. 부산 remains 부산.
It took us about 91 minutes walking around Busan to come to a definite conclusion. No way would 91 days be enough to thoroughly explore this city! The beaches, temples, disparate neighborhoods, mountains, street markets, parks... let alone the food. Koreans are known for their work ethic, and I think we're going to have to follow suit to have any chance of seeing even a fraction of the things Busan offers.