To understand why the Royal Palace sits where it does, you have to know what it stands on. The grounds were once part of the Palace of Coudenberg, the medieval and Renaissance seat of the rulers of the Low Countries. After Coudenberg burned down on the night of 3 February 1731, the ruins sat untouched for more than forty years before Brussels' urban planners finally cleared them in the 1770s, laying out Brussels Park and the Place Royale on top. On the southern edge of the new park, two new mansions went up, joined by a street between them. One served as the residence for the abbot of the nearby Coudenberg Abbey; the other housed senior government officials. These two buildings, joined later by a gallery and given a neoclassical facade, would become the palace. The middle axis of Brussels Park still runs from the front door of the Royal Palace, straight across the park, to the front door of the Belgian Federal Parliament on the other side - a deliberate alignment meant to symbolise the country's constitutional balance between monarch and legislature.

After the Congress of Vienna in 1814-15, the Low Countries were reorganised into the United Kingdom of the Netherlands, with Brussels and The Hague as joint capitals. King William I of the Netherlands needed a palace in Brussels. The street between the two existing mansions was covered, the buildings were joined with a gallery, and the architect Tilman-Francois Suys gave the new composite structure a neoclassical facade with a peristyle and a wrought-iron balcony. William I also built a second palace next door for his crown prince (the future William II of the Netherlands), which is why the square in front is called the Place des Palais - Palaces' Square - in the plural. That second palace is now the Academy Palace, home to five Belgian academies including the Royal Academies for Science and the Arts. Then the Belgian Revolution of 1830-31 happened. William I lost his southern provinces, the new Kingdom of Belgium needed a king, and in 1831 the Royal Palace was offered to Prince Leopold of Saxe-Coburg-Gotha when he ascended the throne as Leopold I, the first King of the Belgians.

Leopold I used the palace for state receptions but lived at Laeken, just as the Belgian royal family does today. His son and successor, Leopold II, found the building too modest. Across his reign (1865-1909), the palace nearly doubled in surface area. Houses between the existing wings were demolished, and two symmetrical curving galleries were added to widen the building dramatically. The king's architect Alphonse Balat - the same architect responsible for the Palace of Fine Arts that houses the Oldmasters Museum nearby - designed the Grand Staircase, the Throne Room, and the Grand Gallery. Balat planned a new facade as well but died before it could be built. After 1904 the architect Henri Maquet executed a different facade, the one visible today, with a pedimental sculpture by Thomas Vincotte showing an allegorical figure of Belgium flanked by Industry and Agriculture. The pediment carries Leopold II's monogram in the floors. Leopold II is also the king whose private property the Congo Free State was, and the same wealth that built much of grand Brussels was generated by extraction and forced labour in central Africa. The palace's grandeur is inseparable from that history.

The Throne Room, despite its name, has no throne. It does have an extraordinary parquet floor in oak, maple, mahogany, and ebony, with Leopold II's monogram inscribed in the wood; red velvet and silk hangings installed by Queen Elisabeth in the early twentieth century; allegorical bas-reliefs of the Meuse and Scheldt rivers by Thomas Vincotte; and a frieze of female figures attributed to Auguste Rodin representing the Belgian provinces and their main industries. The Province of Brabant is missing from the frieze because the palace already sits on Brabant soil. The Empire Room - originally a ballroom decorated under William I - was the room in which Napoleon and his wife Josephine received the authorities of the City of Brussels in 1803. The Goya Room has held three tapestries woven at Spain's Royal Tapestry Factory of Santa Barbara from designs by Francisco de Goya since 1905; they were a gift from Queen Isabella II of Spain to Leopold I. The Coburg Room is a family album in oil paint, with portraits of Leopold I's mother, sister, brother-in-law (Queen Victoria's father), and his German Saxe-Coburg-Saalfeld relations.

Heaven of Delight, Jan Fabre's beetle-wing ceiling, was installed in 2002 in what is now used as the Hall of Mirrors, where the king receives letters of credence from new ambassadors. The wing-cases - elytra - come from buprestid beetles, gathered from the food industry in Thailand where the beetles are eaten and their iridescent shells discarded. Each was individually attached to the ceiling by Fabre and his team. The work has remained in place despite Fabre's 2022 conviction in Belgium for sexual offences against members of his theatre troupe; the palace concluded the artwork's institutional standing was separable from its maker. Since 1965, the Royal Palace has opened to the public every summer from 21 July - Belgian National Day - until early September, Tuesday to Sunday, 10:30 a.m. to 5:00 p.m. The palace is, even in a constitutional monarchy, a place of work: king's office, household services, council meetings, formal receptions of ambassadors and foreign heads of state, and the lying-in-state of a king after his death. Its facade is about 50 per cent longer than Buckingham Palace's; its floor area is less than half. The flag goes up when the king is in the country. The guard of honour stands at the front when he is inside the building. From the Place des Palais you can read the king's day off the palace itself.