Karlsplatz is an open square in Heidelberg’s Altstadt, just south of the Hauptstraße and a short walk from the Church of the Holy Spirit. Its historic buildings and clear view up to Heidelberg Castle make it a worthwhile pause between the old town’s busy lanes and the climb to the castle.
The square occupies the site of a former Franciscan monastery and was named for Karl Friedrich of Baden. At its centre is the Sebastian Münster Fountain, a modern sculpture honouring the Renaissance scholar and cosmographer who taught in Heidelberg. Its geometric forms offer a striking contrast to the surrounding architecture.
Come in the morning for a quieter look at the square and the castle above, or return in winter when seasonal events can bring it to life. Karlsplatz is easy to explore on foot as part of an Altstadt walk; allow around 20 minutes from Bismarckplatz rather than relying on a short transfer. Parking in the old town is limited, so public transport and walking are usually the simpler choice.