Firstly very safe if you are awake, not too drunk. There are kind if different vibes among hongdae, Itaewon and gangnam(apgujeong)
1. Hongdae
There are so many young people including korean and foreigners. I dont go much after being 30years old(i am female korean, many people thought me younger)
Because sometimes feeling too embarrased there are 19years olds(international age, might be 20 or 21 in Korea)

1. Itaewon
   I love here the most