The Royal Greenhouses of Laeken (French for "Les Serres Royales de Laeken") are a complex of royal greenhouses located in Laeken, a district of Brussels, Belgium. These royal greenhouses are one of the most famous tourist attractions in Brussels and can only be visited for a few weeks a year.The greenhouses were built between 1874 and 1905 by King Leopold II as part of the Laeken Castle complex. Their architectural style is a mixture of classical and art nouveau styles, with many wrought iron decorations and stained glass windows.The royal greenhouses at Laeken cover an area of about 2.5 hectares and contain a large collection of exotic and rare plants from all over the world. Among the most interesting plants are palms, giant ferns, orchids, azaleas, and camellias. The greenhouses also contain an extensive system of glass greenhouses and tunnels, which allow for different microclimates to accommodate a wide range of botanical species.The highlight of a visit to the royal greenhouses is the Great Greenhouse, which measures about 100 meters in length and contains many of the largest and rarest plants in the greenhouses. Other interesting greenhouses to visit include the Knight's Greenhouse, the Rhododendron Greenhouse, and the Palm Greenhouse.The Royal Greenhouses in Laeken are only open to the public for a few weeks a year, usually in spring when the plants are in bloom. During this time, the greenhouses are open every day except Mondays. There is a fee to visit the greenhouses and requires the purchase of a ticket, which can be booked online or purchased directly on site.