By the late 1960s, the building occupied by Royale Belge — now AXA — on Rue Royale since 1894 had become too small. A new complex was therefore planned in Watermael-Boitsfort, in an airy, green district. The first stone was laid in 1967 and, three years later, a colossal fully glazed building in the shape of a Greek cross, seemingly floating above a square base, caused a sensation. This bold project was designed by architects René Stapels and Pierre Dufau. Its rust-coloured structure and imposing curtain walls of reflective glass with golden highlights, set in patinated steel, were a true first in Belgium. Inside, the luxurious and modern spaces offered a working environment focused on well-being and efficiency.
After a long period of neglect, the building was fully renovated by a team of architects, while the interior design was entrusted to nearly 52 Belgian and international designers. Transformed into a multifunctional complex, the emblematic building now houses MIX, a vast platform including a four-star hotel, several restaurants, coworking spaces and a highly popular sports centre of more than 5,000 m².