The Royal Museums of Fine Arts of Belgium are in effect four separate museums: the Musée d'Art Ancien (Museum of Old Masters), which covers the 15th to the 17th centuries; the Musée d'Art Moderne, with works from the 19th century onward; the Musée de la Fin de Siècle, which opened in late 2013 and which covers works around the turn of the 20th century; and the Magritte Museum, devoted to the Surrealist genius René Magritte.  As you’d expect, this a huge complex, with over 20,000 works. So how to tackle it? I would recommend first visiting the Old Master Museum, and then coming back another day for the next two. (Since the Magritte Museum is devoted to a single article, its focus and feel is very different; it's covered under a separate entry.) The Museum of Old Masters is a blockbuster, with masterpieces by most of the founders of European art. It's centered around the Southern Netherlands, with many painting from there worth lingering on, including the Portrait of Anthony of Burgundy by Rogier van der Weyden. The "Great Bastard of Burgundy," as its noble subject was known, was one of the illegitimate children of Philip the Good, who ruled over an empire covering most of Belgium in the 15th century. Another standout is Brueghel the Elder's Census at Bethlehem, showing Mary riding a donkey through a snowy Brabant village. Don't miss the significant collection of works by Peter Paul Rubens, including The Ascent to Calvary, plus art by Anthony van Dyck and Jacques Jordaens in the galleries devoted to Flemish art in the 17th and 18th centuries.   The rich collection comes courtesy of Napoléon, who in 1801 founded the museum from works seized during the French Revolution. A visit to Marat Assassiné, Jacques Louis David's dramatic and iconic portrayal of the French Revolutionary stabbed to death in his bath in 1793, makes a fitting end to a visit.  The Museum of Modern Art is being redesigned and rehung after its gallery space was turned over to the Fin-de-Siècle Museum. At this writing a selection of works is being displayed in a changing series of temporary exhibitions in rooms just off the main lobby and in various locations around the museum. As you walk through the museums, you'll come across works by symbolists like Constant Montald and Victor Rousseau, and realists such as Jef Lambeaux and Constantin Meunier, alongside contemporary works, including Thierry De Cordier's Emerald Vision (2009).  The Fin-de-Siècle Museum displays works between 1868, when the Société libre des Beaux-Arts was founded, and 1914, when World War I began. Brussels was at the heart of the flowering of art nouveau, and this museum's four floors cover all the major artistic disciplines it influenced, including painting, sculpture, photography, film, architecture, furniture, jewelry,  and glassware. Some names (van Gosh, Burne-Jones, Bonnard, Sisley) are likely to be familiar, but many others will be happy discoveries, particularly to non-Belgians (Hippolyte Boulenger and Léon Spilliaert are among them). It's a stunning collection showing the wonderful exuberance and explosion of arts and crafts during the belle epoque. After visiting the museum, don't miss the house of Victor Horta, the architect responsible for so many of Brussels's superb art nouveau buildings.