The Punkaharju is a 7-km esker — a long sandy ridge left by retreating glaciers — that runs between Lake Pihlajavesi and Lake Puruvesi about 25 km southeast of Savonlinna. The ridge is sometimes only a few metres wide at the top, with pine forest above and water on both sides, and it is one of the classic landscapes of Finland.
The Punkaharju has been a protected nature area since 1843, one of the oldest in Europe. The historic road and parallel railway run along the spine of the ridge; walking trails and a cycling path provide alternatives. The Lusto Forest Museum (a small museum about Finnish forestry) is at the south end of the ridge. A good day-trip from Savonlinna, easily reached by train.