Seoul has many historical sites, but mostly, it is a city on the move. Full of people and cars, street markets, 24-h shops/restaurants/saunas, thousands of neon lights... The city is alive 24h a day and it really starts living at night, when the Sun goes down and lights lit the city and dye it with millions of colors.
The city is full of street markets and restaurants where you can get everything from seafood to dog soup.
If there is one building which can be seen from many places in the city, that is Seoul Tower, which supervises the city from the top of a mountain.
Seoul also has nice architecture, like this stunning building in the downtown area:
And old buildings are also integrated in the urban landscape in good harmony. This gate is just across the street from the futuristic building before!
Apparently, the city has changed a lot in the last 5/10 years. One of the projects to create a more livable downtown was the creation of a river where people could walk and relax.
The city is full of markets, usually full of people at any time!
Another nice building:
This one is one of the most famous shopping areas, Myung Dong:
In short, Seoul is a vibrant city in whose streets you can get lost for a couple days ;)