Sitting at the one end of London's Millennium Bridge, the Tate Modern, with its 99-metre high smoke-stack tower, rises like a cathedral to modern art on the south bank of the Thames. This massive building was once a power station, generating electricity for much of central London. But since 2000, it's been a leading modern art museum, pumping new energy into London's contemporary art scene. It is home to a dizzying range of styles and movements – pop artists like Roy Lichtenstein, David Hockney and Andy Warhol, alongside surrealists like Picasso and Dali, and abstract artists like Matisse and Jackson Pollock.
The first thing you'll see when you step through its main entrance, however, is almost certain to be unexpected. The giant dimensions of the Tate's Turbine Hall – five storeys high and covering 3,400 square metres – are enough to astonish. But the works of art installed here invariably add to its spectacle of space. It could be the bizarre white stacked-cubes of Rachel Whiteread, or the porcelain sunflower seeds of Ai Weiwei – installations in this temporary exhibition space are usually large, often dramatic and always a challenge.
There's plenty more artistic challenge to be found in the galleries surrounding the Turbine Hall, too. The paintings, sculptures and installations are arranged by floor, according to themes. Poetry and Dream looks at the flights of fancy and the unconscious, with many Surrealist works, whereas Structure and Clarity is full of abstract geometry, expressed through painting, film and sculpture. These galleries are all free, while the main hall charges for its exciting and ground-breaking exhibitions. These often focus on particular modern artists, like Damien Hirst or L.S. Lowry.
Another innovation at the Tate Modern is the recently opened spaces called The Tanks. Here you can see some of the most radical of contemporary art forms – installation, interactive or performance-based, all housed in three underground, interconnected former oil-tanks. The Tate hasn't stopped with its reach for new ideas, though. It is raising funds for a new spiralling glass-tower south of the current museum, which will allow it to show more of its collection in new ways. One thing you can guarantee from your visit to the Tate – it'll never be the same Tate twice.
