One of the largest Baroque palaces in Germany, with a main facade stretching 450 metres across the western end of the grid. The Elector Johann Wilhelm commissioned it in the early 18th century, and it was completed under Karl III Philipp, who moved his court here from Heidelberg. Mozart performed here as a child; the court orchestra was one of the finest in Europe.
The Second World War left it largely in ruins, and the rebuilding took decades. Most of the palace now belongs to the University of Mannheim, which means you can walk the corridors freely on weekdays. The Baroque formal gardens behind the building are well maintained and provide a good view of the long facade from a distance.
The Mannheim orchestra was so influential in the mid-18th century that the "Mannheim rocket" — a rapid ascending scale passage — became a standard compositional device. Mozart visited twice and wrote enthusiastically about what he heard.