The Pompejanum is a full-scale reconstruction of a Roman villa from ancient Pompeii, built on a terrace overlooking the Main river between 1840 and 1850 on the orders of King Ludwig I of Bavaria. It was designed by Friedrich von Gärtner based on the House of Castor and Pollux in Pompeii, incorporating authentic Roman floor plans, fresco painting techniques, and original artefacts brought from Italy.
The interior is furnished with Roman furniture, mosaics, and decorative objects, and the wall paintings — many modelled directly on Pompeian originals — are among the best examples of 19th-century historicist decoration in Germany. The building suffered damage in World War II but has been restored. It sits just downriver from Johannisburg Palace and can be combined with a palace visit in a morning. Open April to October.