The extraordinary beams of light shooting miles into the air from Victoria Tower Gardens may be the most viewed piece of conceptual art ever. Spectra, visible from high points miles away like Primrose Hill, is the extraordinary work of Paris-based artist and composer Ryoji Ikeda, and is produced by art facilitators Artangel.

If, like me, you switched this on feeling sheepish about your sketchy knowledge of Chinese art, you would have welcomed as a ready-made excuse the news that some monuments synonymous with Chinese culture are relatively recent discoveries. It seems unthinkable that the terracotta army guarding the burial site of China’s first Emperor Qin Shi Huang was the stuff of legend and rumour until 1974, but it turns out that much of the 22-square-mile area occupied by the memorial is still to be explored and it could be another century before the site is fully excavated.

The doctoring of political images became something of a tradition in the last century, with Stalin, Hitler and Mao all airbrushing their enemies from photographs. The latest infrared technology has revealed that something similar may have happened during the English Civil War, with a portrait of Oliver Cromwell apparently having been painted over with an image of the Parliamentarian Sir Arthur Hesilrige, who fell out with Cromwell when he became Lord Protector in 1653. 

The Imperial War Museum is one of the most extraordinary museums in the world. Its contents and presentation triumph over the three words of its title, each usually causing dread rather than enthusiasm: imperial (discredited unless to do with Roman history); war (just horrible, and we shouldn’t do it); and museum (well, isn’t that mausoleum?) 

In fact, its collections embrace the modern world, and are perhaps the most insightful and visible tour of modern history that we have. 

The year 1915 was a big one for Kazimir Malevich, as it was for the course of modern art. It was the year the Black Square was first exhibited (June 1915 is the likeliest date of the painting’s execution, though Malevich himself dated it to 1913, insisting it derived from his designs for Futurist opera Victory Over the Sun). A simple black square on a white ground, it presented a gesture so bold, so audacious that it can only be rivalled by Duchamp’s Fountain of 1917.

Do we need more? Over the past 60 years thousands of books and bibliographies about Virginia Woolf (1882-1941) and the group of friends, lovers, spouses, partners, children, and houses with which she is associated, have been published, not to mention movies and plays and a more hidden mountain of academic dissertations. 

It’s 70 years since Mondrian died in New York, leaving unfinished his last painting, Victory Boogie-Woogie, an ebullient title quite at odds with the buttoned-up asceticism we normally associate with this artist. The Courtauld Gallery showed a small survey two years ago, which paired his flat grid compositions with the paintings and white reliefs of Ben Nicholson, focusing only on his two years in London (1938 to 1940).

Rimsky-Korsakov’s bizarre final fantasy, puffing up Pushkin's short verse-tale to unorthodox proportions, has done better in Britain than any of his other operatic fairy-tales. That probably has something to do with its appearance in Paris, six years after the composer’s death in 1908, courtesy of a brave new experiment marshalled by that chameleonic impresario Sergei Diaghilev.

When Ryan Gander’s wife wanted a designer lamp, the versatile artist knocked one up from junk. She was so impressed he sold it as an artwork and by now has made 55 in his garden shed. Three are here in Manchester, made from foil food trays, a guitar stand and concrete. These pieces are quite unrepresentative of the rest of this highly conceptual show, but in a diverse, major survey there appears to be no truly representative way in.

Digital Revolution begins with an archive section taking you back to the 1970s when Ralph Baer developed a video game allowing punters to play ping pong on TV (below right: poster for the original Pong arcade game) and Steve Jobs worked on Break Out, in which a virtual ball bounces off a bank of horizontal lines.