Picnic in Hangang
The river that goes through the whole of Seoul is Hangang. There are many parks along the river, which is called Hangang Park. It is not only for exercising or jogging but Korean people like to go to these parks for picnics.
Something different from other countries, locals like to order delivery rather than bringing their own food. The delivery service in Korea is very convenient. It does not only deliver to homes or offices but even to the parks. There are usually staff that hand out leaflets to people visiting the park. When you call the number on the leaflet, they prepare the food in a short period of time and you can pick it up at a specific point near the picnic area. There is fried chicken, pizza, JaJangMyeon (Noodles in Black Bean Sauce), chicken feet, almost everything you can think of. But usually people like to order fried chicken or pizza and drink beer there.
After filling your stomach, you can go rent a bike with 2000won and go along the Hangang River park for an hour. However, everyone will agree that you should go around sunset or at night. It will be too hot to sit under the sun in the afternoon.
Dongdaemun History Park
I was always amazed by the design of Dongdaemun Design Plaza (DDP). They highlight the futuristic perspective with the design of outer space. They give me the impression of spaceships. When it is day time you can see the sparkling outer surface of the infrastructure, when it is night time the lights add a new perspective to the area.
I think I really like the lighting they use on different places. People might like to visit the Namsan tower in day time for a hike or the clear view of the Seoul city, but I recommend the night view. You can see the moving of lights on the streets with cars. It is like a flash of seconds when you are seeing from up there which is much slower than when you are down there. When you focus back on where you are, beside the tower, the light lightening up the tower changes with the degree of fine dust at that time.
The Lotte World in Jamsil has been there for a while but the outdoor part of Lotte World and Lotte Tower is a newer area in Jamsil. Locals like to visit the Lotte World Mall, it should be too hot to shop outdoor in Summer.
I recommend to find a café that is a bit further from the tower if you want to see the tower rather than looking at it from right below. I have visited the rooftop café “Seoulism” in the evening and the sunset view is great.
The Seokchon Lake right in front of the Lotte Tower and Lotte World is famous for its Cherry Blossom Festival in April. The trees surrounding the lake are full of Cherry blossoms, which is nice to visit when you go to Seoul during the Cherry Blossom season.