During your stay in Korea and Buyeo, don't miss the fortress of Busosanseong to the north of the city. The view from the observatory of Baekhwajeong, above the cliffs and the river, is superb, as are the landscapes you go through to reach it. In my opinion, the spring and autumn, when the trees turn red, are the best moments for this short hike.
The lake of Gungnamji, to the south, is the oldest garden in Korea. A wooden bridge joins the small artificial island in the middle of the lake. The surroundings are beautiful in summer, when the fields of lotus around the lake are in bloom.
If you want to learn more about Korean culture and the ancient kingdom, Baekje Cultural Land is for you. You'll discover the very well-renovated palace, the groups of royal tombs and a cultural village which presents different kinds of homes.