Four free hours in Seoul: What did I do?

I was in Seoul for a conference but had a few free hours, before the conference began, to see some of the sights.
I visited Gyeongbokgung Palace, Cheonggyeceheon Park, and Kwangjang Market before heading back to the hotel.
Only a taste of Korea, but a fun day!

[@REMYDANN]

Been there in 2011