Things to do in Downtown Seoul

I was in Seoul last month for a business trip ... now i am going there again.....

Can anyone sugguest place that i can visit and shopping around downtown Seoul?

Baiscally i have visited Deoksugung Palace, Gyeongbokgung Palace, Changdeokgung Palace, Namdaemun market, Myeongdong street, is there any place that i can go on this trip?

When i was at Lotte shopping the other day, it was close at 8pm.... can anyone let me know if there is a shopping place that is open till 10pm or is there any 24hours shopping complex in Seoul? :)

Definately i will go to Dongdaemun on this trip....any more place to suggest? :)

Thanks

Things to do in Downtown Seoul

Don%26#39;t miss the Coex mall.

http://www.coexmall.com/language/en/

Things to do in Downtown Seoul

I just got back from Seoul and the COEX mall is open until 10 and some stores are open until 10:30. I went to Namsen Tower and the Cheonggyecheon Stream is a nice walk with shops along the way. If you have time during the day the Bongeunsa Temple is really nice to see. Have fun.