Nodeulseom (Nodeul Island) is an artificial island in Han River. It is an uninhabited island that has an Ecological Park where you can visit small farms and experience a glimpse of rural life in the middle of the city.
You can see many people fishing around Nodeul Island or taking pictures of the beautiful scenery around Hangang bridge and Han River.
It's also known as one of the places to see the fantastic annual Seoul Fireworks Festival around October.