The 1st Sium Sium Han River Triathlon Festival inviting participants to complete swimming, cycling, and running events within 48 hours will take place along the Han river in Seoul in June. The Seoul Metropolitan Government announced on Monday that the festival would take place on June 1 and 2 at the Ttukseom Han River Park in Seoul. Under the slogan, “Sium Sium” meaning "chill-out" in Korean, th.