Indeed, the gallery, open since 2000, has just announced record-breaking numbers of visitors, over half a million for Matisse: The Cut-Outs (see review below), making it the most visited gallery of contemporary and modern art in the world.
The new building's shape and roofline is visible only if you go round the back of the main building. Indeed, you'll find not so much a roof as a flat, storied platform, somewhat like the flat-topped ziggurats of old, the precursors of the pyramid forms we know today. The intention then was to act as an interface between earth and sky. I have a feeling that this extension, no less than the great symbolic buildings of the past, and due to open in 2016, will have lessons to teach us about the natural world and the arts.
When complete, the extension's façade will be chequer patterned with glass and terracotta tiles. I imagine it as a kind of glittery brick, well in keeping with with the restrained and beautiful detailing of Tate Modern I.
Go further round the back. The whole of this part of Bankside is transforming. In train with the new building you will find developments that come with woodland integrated into the scheme, and backllit shops that look naturally brighter than any shops you've ever seen. There are coffee shops, places to sit, picnic areas - and great views.
These art museums are places where the permanent collections are free to visit. These are places where the paid-for exhibitions come complete with lectures, courses, talks, and events for children. For, unlike the ziggurats of old, where the priests ascended during fire or flood and the non priests stayed below, this is art for all.
As an endnote, consider that none of this easy accessibility to modern art would be possible without the Millennium Bridge linking it all together, opened in 2000, and Lord Foster and Arup's enduring triumph.
At Tate Modern Level 3 until Sunday 26 October, Kazimir Malevich (see review below)