Buildings can become missiles. An example is St. Peter’s Basilica in the Vatican, which Luther turned into a symbol of the degradation of the Catholic Church. So is the new seat of the European Council in Brussels. David Cameron came to express “immense frustration” at the cost of erecting it, 320 million euros, and tried unsuccessfully to block the project. Now, months after the United Kingdom voted for Brexit, the controversial edifice has been dedicated quietly, perhaps to avoid polemic in times not warranting celebrations. But the EU Council’s new Europa building cannot help attracting attention. Designed by the Belgian office of Philippe Samyn in collaboration with the Italian firm Studio Valle, it appropriates an apartment building of the 1920s and completes the block with a construction organized with efficiency but characterized by a changing image. By day the facade presents a filigree of 3,750 recycled wooden frames, and at dusk this skin reveals a glass-clad egg containing the building’s functional heart, nicknamed ‘Egg in a Cage,’ where EU leaders will face each other around a circular table in summits, starting this year. A disturbing symbol, perhaps, of the simultaneously permeable and opaque nature of the European Union itself.