It's been compared, possibly with fairness, to both a bathtub and a kitchen sink. Indeed, "the bathtub" appears to be its unofficial nickname, coined by lead architect Mels Crouwel. What's undeniable is that the newly-completed extension to Amsterdam's Stedelijk Museum is different, and in a very specific sense.

The expansive white addition to the building, designed Benthem Crouwel Architects, couldn't look more different to the museum's existing 19th century red brick construction designed by Adriaan Willem Weissman. The received wisdom (though perhaps not among architects themselves) that extensions should do their utmost to match their architectural progenitor has clearly been rejected. But distinctiveness does not necessarily imply dissonance.

Running the entire length of the museum, the extension, which is made from reinforced fiber, has a footprint of 98,400 ft2 (about 9,100 m2) and gives the building a new entrance and front façade on Museumplein, not to mention a new, iconic visual identity which is almost certain to polarize opinion.

The museum is set to reopen September 23.

Sources: Benthem Crouwel Architects and Stedelijk Museum, via Dezeen