Here's something you see in Korea all the time: Demonstrations.
Every couple of days, sometimes everyday, you see around town, police buses and policemen standing around with shields and helmets in groups. Usually you don't see the protestors as they have not arrived yet. Demonstration organisers have to give notice to the police of any demo they are planning. We have seen them get violent only a couple of times. Normally the protestors all just sit or stand in the road and listen to speeches.
This one today was larger than average with a stage built and several lanes of the road cordoned off. Sometimes there is just a small portable stage on the back of a truck and some speakers.
Here is a little experiment of a video I took of them protesting this afternoon in Yeouido on the road in front of the National Assembly building.
They are still going on now at 19:30 and I can hear them from the apartment even with the windows closed to give you an idea of how loud it is!
Sadly I have got no idea what they are on about. Any ideas?
UPDATE: I've been told one of the signs is for the Korean Health and medical workers Union
who have a webpage in English.