Far cleaner than Seoul, but still a big city with a large ex-pat population, Busan is one of the better areas to gain employment in South Korea.
A little more difficult to find work in than Busan, Jeju is a very desirable area of South Korea to work in, as it is often referred to as "Korea's Hawaii."
Sure, it's pretty smoggy and excessively populated, but there really isn't a city like it, with a pretty decent nightlife and a lot of fantastic food. (Perhaps not the best spot for those with bad asthma, however.)
On the water, and an extremely nice downtown area that's reminiscent of San Francisco with the uphill streets, Geoje is another great place to spend a year or two. In addition, it also has a fairly decent ex-pat population, and a local movie theatre that plays Western movies.
Still fairly populated at approximately 2.5 million, and quite clean when compared to Busan or Seoul, Daegu is another great spot for those who are new to overseas travel. There's still enough Western influence for newbie travelers to feel comfortable, but not too much to make it feel as if you're in 'Koreatown' back west.
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