<Seoul's Smile> is a work by Kim Young-sik, installed inside the Sejong Center for the Performing Arts, behind the Sejong Center for the Performing Arts. ‘Seoul’s Smile’ is based on the onomatopoeic word ‘hahaha’ that describes laughter. By reinterpreting the geometric formative elements of Hangeul and constructing them three-dimensionally, the excellent aesthetic formativeness of Hangeul is revived, and by visually embodying the sound of laughter, the bright Seoul and the happy expression of Seoul citizens are symbolically represented.