This week, amateur gardeners have started moving citrus and rosemary trees indoors as temperatures fell to around 12 °C. These plants are sensitive to cold and require protection to avoid damage. A similar practice is carried out on a larger scale at the Palace of Versailles, where more than 1,000 trees, some over 200 years old, are relocated to the Orangerie each October for the winter. The Orangerie, a historic building constructed 340 years ago, serves as a shelter for these plants during colder months. The Orangerie does not have a heating system, but its design helps maintain a stable temperature. The walls, which are 4 to 5 meters thick, help to reduce temperature differences between day and night. The building's southern orientation allows winter sunlight to enter through large windows, warming the interior. The temperature inside never drops below 5 °C, which is crucial for protecting the trees. The current Orangerie was built by Jules Hardouin-Mansart between 1684 and 1686, expanding an earlier structure designed by Le Vau in 1663. The Orangerie has a central gallery over 150 meters long, with a vault 13 meters high and double-glazed windows. According to the palace, the building’s design, including its orientation, thick walls, and winter precautions, ensures it never experiences frost. The structure is also partly underground, located under the Parterre du Midi. During the Ancien Régime, gardeners used large cat flaps to enter the Orangerie, avoiding the need to open large window doors. These doors were sealed with straw to prevent cold air from entering. The original purpose of the Orangerie was grand, with the palace’s educational materials noting that it was intended to house nearly 3,000 citrus trees during the time of Louis XIV. The trees return to the parterre around mid-May, where they spend the warmer months among the six grass compartments and the circular basin of the Orangerie's parterre. In summer, the palace counts 1,055 trees in boxes on the parterre, including oranges, palms, rosemary, and pomegranates. Some of these trees are over 200 years old. The same practice is observed in conservatories and private terraces, with only a few hundred fewer trees moved. The palace has not yet announced a specific date for the 2026 return of the trees.