Obelisk, Cultural heritage monument in Old Market Square, Potsdam, Germany.

The Obelisk on the Old Market Square is a multi-sided stone pillar decorated with classical details that stands out clearly from the surrounding buildings. The structure displays clean lines and geometric forms typical of Prussian architecture from this period.

Built from 1753 to 1755 on a design by Georg Wenzeslaus von Knobelsdorff for Frederick the Great, the obelisk was part of the remodelling of the Old Market into a square quoting Roman models. Its four marble medallions by Benjamin Giese showed the Prussian electors and kings Frederick William, Frederick I, Frederick William I and Frederick II. Badly damaged in the air raid of 14 April 1945, it was dismantled down to its base in 1969 and rebuilt in 1978/79.

The four marble medallions on the shaft, carved by Benjamin Giese, first showed profiles of the Prussian electors and kings Frederick William, Frederick I, Frederick William I and Frederick II. After the 1978–79 rebuilding they were replaced by reliefs of architects who built on the Old Market: Knobelsdorff, Gontard, Schinkel and Persius, made by Rudolf Böhm and Walter Rentzsch.

The obelisk stands at the exact intersection of the central axes of the Nikolaikirche, the Altes Rathaus and the Palast Barberini, so it can be used as a fixed point for orientation on the square. It is almost 25 metres high, with a 16-metre shaft above the marble base.

The obelisk was rebuilt in 1978–79 after wartime damage, and its four portrait medallions were changed: instead of Prussian electors and kings, they now show the architects who built on the Old Market — Knobelsdorff, Gontard, Schinkel and Persius, carved by Rudolf Böhm and Walter Rentzsch. This makes it, in Germany, a rare case of a princes' monument turned architects' monument.