The Brandenburg Gate on Luisenplatz in Potsdam was built in 1770/71 by Carl von Gontard and Georg Christian Unger on behalf of Frederick II. It stands at the western end of Brandenburger Straße, which runs in a straight line to the Church of St. Peter and Paul. Along with the Jägertor and the Nauener Tor, it is one of Potsdam's three surviving city gates.
Previously, in 1733, there was another, simpler gate on the same site, resembling a city gate. Together with the city wall, a kind of toll wall or excise wall, and the other gates, it was intended to prevent desertion and smuggling.
Towards the end of the Seven Years' War, Frederick the Great had the old gate demolished and a new one, the Brandenburg Gate, built on its site as a symbol of victory. For this reason, the Brandenburg Gate resembles a Roman triumphal arch. It was modeled on the Arch of Constantine in Rome. The Roman influence in the architectural style is evident, among other things, in the Corinthian twin columns and the strongly corbelled entablature.
Characteristic of the Brandenburg Gate are its two completely different sides, which can be traced back to two architects: Carl von Gontard designed the city side, and his student Georg Christian Unger the field or land side. Gontard designed the city side as a plaster façade with Corinthian pilasters and trophies, while Unger designed the land side in reference to the Arch of Constantine with Corinthian twin columns and decorations such as the golden trumpets. The two side passages for pedestrians were only added in 1843 under Frederick William IV to accommodate the increased passenger volume.
At that time, one had to pass through the Brandenburg Gate if one wanted to make one's way to the city of Brandenburg, hence the name. The gate leads the walker eastward through the inner-city pedestrian zone of Brandenburger Straße to the Church of St. Peter and Paul.
Since the demolition of the city wall around 1900, the Brandenburg Gate has been a freestanding structure.
(Source: Wikipedia)