Tate Modern reopening: 'We've never needed these unsettling visions more'

The best modern art was made in times of crisis and terror, meaning this museum has never been a relaxing place to visit. But where better to discover the true meaning of a changed world?When Tate Modern first opened its doors 20 years ago, modern life seemed comparatively benign. At the opening party, JG Ballard looked on ironically from a balcony as a brass band played acid house anthems and shiny happy people queued to climb a Louise Bourgeois tower. It is about to open again. But the world h