Big day today! After watching The Depot rise from the ground over the past couple of years like a big shiny bowl, this annex of the Museum Boijmans Van Beuningen in Rotterdam was finally ready to open its doors. There is still a year to go before it is finished and full of works of art but this weekend was the Silver Opening and the press and the public were allowed in to have a look around and see the work in progress.

It’s a well-known fact that any museum can only display a very small percentage of its collection – usually well under ten – at any one time. The majority of work is stored somewhere else, out of reach and out of sight. In the case of Boijmans, the 150,000-odd works of art were stored in the basement.

Another well-known fact is that a lot of Holland is below sea level and consequently things can get a little damp underfoot if you go much below the surface. Chronic flooding was the problem with the Boijmans’ basement. But rather than build a dry Fort Knox stronghold with razor wire, search lights and eager dogs somewhere outside the city to keep the billions of euros worth of art safe and dry, it was decided to create a world first – a storage facility that was easily accessible and visible to the public, right next door to the main museum and right in the middle of town.

But not only that, the building itself is something very special and, although it’s not strictly a museum in the true sense of the word, it will rank alongside the Guggenheims in New York and Bilboa and the Pompidou in Paris as an iconic and worthy shrine to the glories of art.

In a city that is renowned for its original and innovative architecture, The Depot raises the bar a few more notches. Its mirror-covered exterior is like a giant fish-eye lens, a kaleidoscope providing an ever-changing view and perspective, albeit distorted, of Rotterdam and its huge sky.

The inside, we discovered today after we’d been issued with our hard-hats, is just as spectacular though more utilitarian. The stairs and lifts that rise through the centre of the building are like something out of a Piranesi drawing, or, much closer to home, an Escher puzzle house. It is like being in the belly of a benevolent machine with girders, rivets, lifts, pulleys and chains straining at the leash.

Spread over five floors are the storage rooms, each with sliding metal racks on which the pictures will hang. Each room is temperature, light and humidity controlled to provide the ideal environment, whether it be for an old master oil painting on an ancient wooden panel or a modern colour photograph. They’ll be safe and pampered in The Depot. There are rooms for the conservators to preen and clean the artworks even more.

But we haven’t finished yet. As if the outside of The Depot wasn’t spectacular enough nor the inside suitably impressive, the building’s crowning glory is on another level, literally, and provides a tranquil haven in which to relax. The forty-meter diameter flat roof, one hundred and thirty feet above the ground, is planted with dozens of five-meter-high silver birch trees and the spacious terraces provide an ideal spot from where one will be able to gaze over the city skyline while sipping a nice glass of wine or, if the weather is inclement, eating in the roof restaurant. You’ll feel just as pampered as the artworks downstairs.

The Depot is the brainchild of Boijmans director Sjarel Ex and Rotterdam architect Winy Maas of MVRDV who will no doubt be the recipients of many prizes and awards in the next couple of years. And although the building will not be fully functioning and open until September 2021 it is well worth a visit just to stare, with your mouth open, at the exterior. Take a chair and some sandwiches and make a day of it because the display changes every second of every day. A wonder of our time.   Michael Hasted   24th September 2020

Listen to the ArtsTalk Radio programme direct from The Depot on the Silver Opening preview weekend and includes an interview with Boijmans director Sjarel Ex