Capital ofBrussels.

The building that invented Art Nouveau — designed by Horta in 1893 for engineer Émile Tassel, it was the first building in history to use structural iron exposed as a decorative element, the first to eliminate the corridor in favour of an open plan, and the first to integrate every decorative element (floor tiles, wall paintings, ironwork, furniture) into a single unified interior scheme. It is a private home; you can only see the facade. The facade is enough — every Art Nouveau building built afterward copied its logic.

The Matongé quarter of Ixelles is Brussels' Congolese neighbourhood — the most vibrant African neighbourhood in northern Europe, named after a district in Kinshasa. Congolese restaurants (moambe chicken, pondu, fufu), Afro hair salons, music shops selling soukous and ndombolo, fabric shops with West and Central African textiles. The area is directly adjacent to the EU institutions and the Louise Avenue luxury shopping strip — the contrast between the two worlds separated by a tram stop is one of Brussels' specific qualities.

The most extraordinary set of glasshouses in Europe — 11 linked Art Nouveau iron-and-glass greenhouses built by Alphonse Balat for King Leopold II from 1874 to 1895, covering 2.5 hectares of royal gardens. Open to the public for approximately three weeks each spring (late April–May) when the azaleas, camellias and tropical plants are in bloom. Outside this window they are closed completely. If you visit Brussels in spring, check the dates: this is the single most special thing to see.

The battlefield where Napoleon was defeated on 18 June 1815 — the most consequential single day in 19th-century European history, fought 15km south of Brussels. The Memorial 1815 museum (opened 2015 for the bicentenary) is excellent: immersive, multilingual, with the actual topography of the battlefield accessible on foot. The Lion's Mound (a 43-metre artificial hill built by the Dutch in 1826) gives a panoramic view of the entire field. Victor Hugo wrote much of Les Misérables's Waterloo chapter from an inn across the road.

The Royal Museum for Central Africa in Tervuren — built by Leopold II in 1910 to celebrate his Congo Free State colony, now radically reinterpreted after a €66 million renovation (reopened 2018). The museum's collection of 180,000 Central African objects is one of the most significant in the world; the renovation grapples explicitly with the colonial violence through which it was assembled. The neoclassical building in a forest park, reached by a 19th-century tram, is spectacular. The tension between the architecture and the reckoning inside it is the museum's subject.