Seo Hyuk-jun, 36, knelt before the white chrysanthemums as he placed a lit cigarette, incense and a paper cup filled with Jack Daniel’s on the ground. He stood, knelt and bowed twice, performing a traditional Korean ritual for the dead.

Day after day, such tributes arrived at the makeshift memorial in Itaewon, one of Seoul’s most popular districts. Young South Koreans used to go there for its diversity and vibrant nightlife. They called it "Itaewon freedom.”

Now, the neighborhood has become a sobering monument of grief and soul-searching after more than 150 young ​people were killed Oct. 29 during a crowd crush while celebrating Halloween. Bars that were throbbing with K-pop music just a week ago are now silent, their doors covered with condolence messages and a notice from the local government asking people to refrain from loud music and dancing.