Miroslaw Balka, Tate Modern, London

Confused people in the dark need to think outside the box

Go for a spin on the London Eye! Gawp at the living statues! Pop into Tate Modern for a disturbing meditation on the physical manifestation of the Holocaust!

The Unilever Series at Tate Modern is in its 10th year, and the gallery is such a popular fixture on the tourist trail of London's South Bank that some of its more explicitly sombre commissions – such as the latest, How It Is, Miroslaw Balka's great, dark box brooding away at the end of the Turbine Hall – struggle to maintain their dignity. This isn't surprising: more than 12,000 visitors a day swarmed up the installation's ramp in its first days, vanishing into the maw, mobiles glowing.

And by the time we had stumbled against the rear wall and dumped our backpacks on the floor to make little Blair Witchy videos in the gloom, we realised that we were standing in what looks like a giant shipping container, the interior of its three remaining walls coated with a sort of velour.

But Balka's installation should not be judged on the sum of those parts. Indeed, wandering up the ramp and into total darkness is deliciously bewildering. Blink a few times, let the eyes adjust, and the ghostly forms of other visitors hover in the distance. At first, it's tricky to tell whether they're an optical illusion, or perhaps even a memory. By the time you reach the back of the box and turn round, your powers of vision are restored, if only to see those entering behind you – arms outstretched, edging forward, blind silhouettes against the entrance.

Which is probably the point at which – standing in a dark room filling with confused people – I might have thought about the Holocaust, as prompted by the exhibition blurb. But I didn't. Instead, other allegories suggested themselves as the gloom lifted: of experience? Deliverance? Disorienting as it is, there's a beginning, middle and end to this experience, quite different from, say, Blind Light, the mist-filled room at the Hayward Gallery that Antony Gormley invited us to grope our way around a couple of years ago.

Anyway, back to us pesky tourists. The longer we stand there, the more it dawns that we could get away with a bit of grafitti in here, or maybe even a snog. The best of the Unilever commissions seem to embrace the carnivalesque (Carsten Höller's slides!). Balka hasn't tapped that vein, but perhaps the Turbine Hall visitors will do it for him over the coming months.

Until 5 Apr, 2010