FOR five centuries Berlin grew out from its political centre, the castle of the Hohenzollerns, as the dynasty rose from imperial electors of Brandenburg to kings of Prussia and finally emperors of Germany. The expanding edifice reflected this. Andreas Schlüter, a Baroque star, made it grand in the 18th century. Karl-Friedrich Schinkel, a 19th-century titan, surrounded it with neoclassical temples.
When the last Kaiser fled into Dutch exile in 1918, the building ceased to be a power center. After 1945 it also stopped being the city’s heart, because the bombed-out ruin was in the Soviet sector. In 1950 the East Germans blew up this symbol of Prussian imperialism, replacing it in the 1970s with a “palace of the republic”, an architectural atrocity with orange windows and asbestos inside.
After reunification and the capital’s return from Bonn to Berlin, the question of what to do with this historic space arose again. The Bundestag and chancellery were farther west, beyond the Brandenburg Gate that marked the old city boundary. The castle’s site was to have a vaguely cultural function. But…