Hongdae Ttaengttaeng Geori is a 215-meter railway walking path that runs between Seogyo-dong and Nogosan-dong in Mapo-gu, Seoul. The name comes from the warning sound that rang with the crossing barriers whenever a train passed, and the path is known as the origin of Hongdae culture, represented by music and art. To reach it, go up the stairs next to Wawoo Bridge on Gyeongui Line Book Street and walk straight, or walk about 361 meters from Exit 2 of Seogang University Station. The site has a public restroom.