I've been to Seoul several times and always noticed this bridge when leaving on the bus. A few weeks ago there were no lights at around 21:50, but when I left on the bus at 22:00 I saw the lights on. So I knew they turn them on at 22:00. I would have to take the 23:50 bus in order to take pictures of the bridge. Funny thing is that when I left on the 23:50 bus after taking these shots, the lights were off! I guess they're on only from 22:00 to about 23:30. Seems like such a short time.