Around Insadong and Jongro 3-ga you'll find a large number of senior citizens just hanging out. This is especially true of Tapgol Park. I was discussing this with Fatman Seoul and he told me there was a reason for this. Back in the day, Jongro 3-ga was the hip place for all the youngsters to hang out at. So, they've just come back home.
P.S. I wonder what Myeongdong will look like in 30 years then?