Question: which landmark built on the site of a former city gate that marked the start of the road from Berlin to the town of Brandenburg an der Havel, is Frederick William II of Prussia responsible for?

full_context: Document 1: Prince Frederick of Orange-Nassau: Frederick, Prince of Orange-Nassau (English: William George Frederick , Dutch: "Willem George Frederik" ; 15 February 1774 6 January 1799) was the youngest son of William V, Prince of Orange and Stadtholder of the Dutch Republic and Princess Wilhelmina of Prussia, sister of King Frederick William II. Commonly called Fritz inside the family, he chose a military career with the Holy Roman Empire, he died of a fever while serving in Padua, Italy.
Document 2: Prince Henry of Prussia (1726–1802): Frederick Henry Louis (German: "Friedrich Heinrich Ludwig" ) (18 January 1726 – 3 August 1802), commonly known as Henry ("Heinrich "), was a Prince of Prussia and the younger brother of Frederick the Great. He also served as a general and statesman, leading Prussian armies in the Silesian Wars and the Seven Years' War, having never lost a battle in the latter. In 1786, he was suggested as a candidate for a monarch for the United States.
Document 3: Hans Hermann von Katte: Hans Hermann von Katte (28 February 1704 – 6 November 1730) was a Lieutenant of the Prussian Army and the friend of the future King Frederick II of Prussia, who was at the time the Crown Prince. He was executed by Frederick's father King Frederick William I of Prussia when Frederick II plotted to escape from the Kingdom of Prussia to the Kingdom of Great Britain. Some believe that Frederick intended to defect to the service of George II of Great Britain (Frederick William's maternal first cousin and Frederick's maternal uncle) and possibly return to Prussia to depose Frederick William.
Document 4: Brandenburg Gate: The Brandenburg Gate (German: "Brandenburger Tor" ) is an 18th-century neoclassical monument in Berlin, built on the orders of Prussian king Frederick William II after the (temporarily) successful restoration of order during the early Batavian Revolution. One of the best-known landmarks of Germany, it was built on the site of a former city gate that marked the start of the road from Berlin to the town of Brandenburg an der Havel, which used to be capital of the Margraviate of Brandenburg.
Document 5: Politics of Berlin: Berlin is a city-state and the capital of the Federal Republic of Germany. The President of Germany, whose functions are primarily ceremonial under the German constitution, has his official residence in Schloss Bellevue. Berlin is the seat of the German executive, housed in the Chancellery (the "Bundeskanzleramt"). Facing the Chancellery is the Bundestag, the German Parliament, housed in the renovated Reichstag building since the government's move to Berlin in 1998. The Bundesrat ("federal council", functioning as an upper house) represents the Federal States ("Bundesländer") of Germany and has its seat at the former Prussian House of Lords.
Document 6: Königsberg fortifications: The fortifications of the former East Prussian capital Königsberg (now Kaliningrad) consist of numerous defensive walls, forts, bastions and other structures. They make up the First and the Second Defensive Belt, built in 1626—1634 and 1843—1859, respectively. The 15 metre-thick First Belt was erected due to Königsberg's vulnerability during the Polish–Swedish wars. The Second Belt was largely constructed on the place of the first one, which was in a bad condition. The new belt included twelve bastions, three ravelins, seven spoil banks and two fortresses, surrounded by water moat. Ten brick gates served as entrances and passages through defensive lines and were equipped with moveable bridges.
Document 7: Frederick William II of Prussia: Frederick William II (German: "Friedrich Wilhelm II." ; 25 September 1744 – 16 November 1797) was King of Prussia, from 1786 until his death. He was in personal union the Prince-elector of Brandenburg and (via the Orange-Nassau inheritance of his grandfather) sovereign prince of the Canton of Neuchâtel. Pleasure-loving and indolent, he is seen as the antithesis to his predecessor, Frederick II. Under his reign, Prussia was weakened internally and externally, and he failed to deal adequately with the challenges to the existing order posed by the French Revolution. His religious policies were directed against the Enlightenment and aimed at restoring a traditional Protestantism. However, he was a patron of the arts and responsible for the construction of some notable buildings, among them the Brandenburg Gate in Berlin.
Document 8: Brandenburg Hauptbahnhof: Brandenburg Hauptbahnhof is the main railway station in the town of Brandenburg an der Havel in the German state of Brandenburg. It lies on the Berlin–Magdeburg railway at the junction with the Brandenburg Towns Railway. It has largely lost its former major role for long-distance passenger services and freight traffic, but it continues to serve regional traffic. A water tower on the site of the former freight yard and a plaque commemorating French forced labourers at the station buildings are heritage-listed. The station was renamed "Brandenburg Hauptbahnhof" at the end of World War II, previously it had been called "Brandenburg Rb" (Rb for Deutsche Reichsbahn) station. It is classified by Deutsche Bahn as a category 3 station.
Document 9: Frederick the Great: Frederick II (German: "Friedrich" ; 24 January 171217 August 1786) was King of Prussia from 1740 until 1786, the longest reign of any Hohenzollern king. His most significant accomplishments during his reign included his military victories, his reorganization of Prussian armies, his patronage of the arts and the Enlightenment in Prussia, and his final success against great odds in the Seven Years' War. Frederick was the last titled King in Prussia and declared himself King of Prussia after achieving full sovereignty for all historical Prussian lands. Prussia had greatly increased its territories and became a leading military power in Europe under his rule. He became known as Frederick the Great ("Friedrich der Große ") and was affectionately nicknamed "Der Alte Fritz " ("Old Fritz") by the Prussian and later by all German people.
Document 10: Ishtar Gate: The Ishtar Gate (Arabic: بوابة عشتار‎ ‎ , Persian: دروازه ایشتار‎ ‎ ) was the eighth gate to the inner city of Babylon. It was constructed in about 575 BCE by order of King Nebuchadnezzar II on the north side of the city. It was excavated in the early 20th century and a reconstruction using original bricks is now shown in the Pergamon Museum, Berlin.
Document 11: Brandenburg an der Havel: Brandenburg an der Havel (also called Brandenburg or Brandenburg City in English) is a town in Brandenburg, Germany, which served as the capital of the Margraviate of Brandenburg until replaced by Berlin in 1417.
Document 12: Market Gate of Miletus: The Market Gate of Miletus (German: "das Markttor von Milet" ) is a large marble monument in the Pergamon Museum in Berlin, Germany. It was built in Miletus in the 2nd century AD and destroyed in an earthquake in the 10th or 11th century. In the early 1900s, it was excavated, rebuilt, and placed on display in the museum. Only fragments had survived and reconstruction involved significant new material, a practice which generated criticism of the museum. The gate was damaged in World War II and underwent restoration in the 1950s. Further restoration work took place in the first decade of the 21st century.
Document 13: George Frederick II, Margrave of Brandenburg-Ansbach: George Frederick II, Margrave of Brandenburg-Ansbach
Document 14: Joseph II, Holy Roman Emperor: Joseph II (Joseph Benedikt Anton Michael Adam; 13 March 1741 – 20 February 1790) was Holy Roman Emperor from 1765 to 1790 and ruler of the Habsburg lands from 1780 to 1790. He was the eldest son of Empress Maria Theresa and her husband, Emperor Francis I, and was the brother of Marie Antoinette. He was thus the first ruler in the Austrian dominions of the House of Lorraine, styled Habsburg-Lorraine. Joseph was a proponent of enlightened absolutism; however, his commitment to modernizing reforms subsequently engendered significant opposition, which eventually culminated in an ultimate failure to fully implement his programmes. He has been ranked, with Catherine the Great of Russia and Frederick the Great of Prussia, as one of the three great Enlightenment monarchs. His policies are now known as Josephinism. He died with no sons and was succeeded by his younger brother, Leopold II.
Document 15: Frederick William II of Prussia: Frederick William II (German: "Friedrich Wilhelm II." ; 25 September 1744 – 16 November 1797) was King of Prussia, from 1786 until his death. He was in personal union the Prince-elector of Brandenburg and (via the Orange-Nassau inheritance of his grandfather) sovereign prince of the Canton of Neuchâtel. Pleasure-loving and indolent, he is seen as the antithesis to his predecessor, Frederick II. Under his reign, Prussia was weakened internally and externally, and he failed to deal adequately with the challenges to the existing order posed by the French Revolution. His religious policies were directed against the Enlightenment and aimed at restoring a traditional Protestantism. However, he was a patron of the arts and responsible for the construction of some notable buildings, among them the Brandenburg Gate in Berlin.
ground_truth: Brandenburg Gate