Palace of Versailles

The Palace of Versailles is the most visited palace in France. The UNESCO World Heritage Site welcomes approximately 15 million visitors annually. It is simultaneously a royal residence, a history museum, and a national palace. The grounds of the Palace of Versailles are state-owned and cover approximately 787 hectares. Over 100 rooms in the palace testify to the splendor of the former royal residence, while around 100 other rooms, covering over 10,000 square meters, house the remarkable collection of paintings and sculptures of the Musée de l'Histoire de France, founded by Louis-Philippe in 1837.As a small hunting lodge belonging to Louis XIII, it once aroused ridicule among the nobility, so the king had it expanded between 1631 and 1634 into a three-winged palace, which still forms the core of the monument today. Under his son, the "Sun King" Louis XIV, the conversion of the hunting lodge into a palace began. Versailles was to become the center of royal power under the young king. In 1667, it was declared the future seat of government, and the court began to move from Paris to Versailles.
The palace's most famous room is the Hall of Mirrors. It is almost 75 meters long and 10 meters wide. Its Mirror Gallery ("Galerie des Glaces") consists of 357 mirror surfaces and serves a very specific function: The mirrors are positioned opposite the 17 floor-to-ceiling windows, thus "bringing" the park into the hall.
Even after the palace was no longer inhabited after the French Revolution, the Hall of Mirrors remained a place steeped in history and fate:
The Prussian King Wilhelm I had himself proclaimed German Emperor there in 1871, and the First World War was ended on the same spot in 1919 with the Treaty of Versailles.de.france.fr/de/paris/artikel/schloss-versailles

Feel free to set aside a whole day for it. With the 1.5 hour as insinuated by the site you will not get there.

Anyone planning to visit the castle should be there early because the line is incredibly long. To the park you get fast entry and alone to visit this, takes a whole day to complete and a fully met.