It's a little city alongside the coast with intricate alleys, though the cafes, bookstores, and places to eat concealed in it generally give travellers a great deal of surprises, Specifically Sonmokseoga. The ticket is only one way, I personally assumed the views from the Cheongsapo Station are a little nicer https://kameron2sz85.ageeksblog.com/33078125/5-tips-about-haeundae-ocean-you-can-use-today