The Unilever Series: The Tate has a cracking show

It doesn't seem so long ago that contemporary visual art was a rather retiring field of activity. Modern art galleries were places of quiet contemplation and reflection for serious-minded souls. You probably didn't take the kids. There was always a risk of being slightly bored. It was important. It was quite small scale. And, though large lumps of Henry Moore would from time to time appear in public places, they were generally overlooked. Art as a rule didn't try and mix it with the wider world, or become a focal point for big gatherings, or – God forbid – a visitor attraction.

All changed. All changed. In the past 15 years, contemporary art has become famous: not famous for being either bizarre or ridiculous, either, but (like properly famous things) famous for being famous. And one reason for this, among many, is that it has lost its inhibitions about both size and the outside world. It got big in every sense, and sought public attention. Many of the most eye-catching artworks of recent years have been outdoors: Antony Gormley's Angel of the North topping the bill, Rachel Whiteread's House in east London, and the occupants of the fourth plinth in Trafalgar Square – works that have attracted far more notice than public sculptures ever used to, and have spawned a new generation of clones, as every City and County council now wants its own Angel.

But at the same time another genre has been born: the big indoor art spectacular. Again, Gormley is a leader, with his massed body-sculptures in the Baltic Arts Centre on Tyneside, and lately with his great chamber of fog in the Hayward Gallery. But the real home of these shows is Tate Modern. Ever since its inauguration in 2000, it has hosted a succession of colossal installations. Sponsored by Unilever, they appear, each autumn, in its vast and cavernous Turbine Hall, itself a kind of indoor-outdoor space. Over seven years the project has produced a handful of triumphant spectacles, grand popular entertainments, of which Imperial Rome need not have been ashamed.

The gallery opened with Louise Bourgeois' gigantic spider, Maman, looming over the central mezzanine. (Bourgeois is now back at Tate Modern, with a full-scale retrospective, and the spider is back too, but outside the building.) It was followed by some even more sublime and stupendous exhibits. There was Anish Kapoor's Marsyas, a cross between a trumpet and an internal organ, its bright red skin of tightly stretched PVC membrane opening into deep orifices, filling half the length of the Hall.

Olafur Elliason's The Weather Project moved things up a step further. Here, a great baleful solar disc of sodium light hovered high at the end of the Turbine Hall, bathed in mists, and with a huge ceiling mirror doubling the visual volume of the space. It set a still unsurpassed standard of theatricality. People gazed into the light for hours, basked and took picnics on the gallery floor beneath it as if it were a real sun.

Last year there was Carsten Holler's Test Site – the helter-skelters, five great glass-and-metal tubes, descending, looping and twisting through the Hall. It was probably the most popular of the shows, with queues of people waiting to take the plunge and be delivered, seconds later – rattled but generally smiling – on to the ground floor. When Tate Modern opened it was compared to a cathedral. Now it seemed a fun fair. And though Tate Modern always keeps a very straight face, a fun-fair reputation could do no harm to its equally spectacular attendance figures.

Tomorrow Shibboleth, by the Colombian artist Doris Salcedo, will open to the public. It is a more sober work, but absolutely up to standard. The artist has emptied the Turbine Hall entirely, exhibiting nothing – nothing, except a deep earthquake crack, literally cut into the concrete floor underfoot. It begins just inside the entrance, as a barely visible meandering rivulet of fissure. Gradually, as it proceeds, it opens and deepens and begins to zig-zag wildly across the floor, moving like forked lightning, with branching cracks splitting off here and there. It runs under the mezzanine, and into the rear section of the Hall, and continues to the very end, where, still going strong, it seems to disappear under the back wall.

It's an extremely well-achieved effect. The view from the entrance is delightful. It is a remarkable sight to see, and to imagine how it was made is another source of wonder. There is no sign at all of heavy work. It's as if the crack really had just appeared, overnight. And I imagine they must have had to take up and relay the floor, or parts of it, rather than simply drill into it, because when you peer into the crack at your feet – it's never more that a foot wide – it reveals realistically moulded rocky walls on either side, going down to some depth, before they close together, but with still a hint of darker depths beneath.

OK, it would be an exaggeration to say that the ground under Tate Modern seems to be literally breaking apart. It is not a frightening or disorientating illusion. Well, it's not really an illusion at all, because it's visibly a fabrication. Those rocky innards are obviously a crafted formation, not what would really appear beneath the museum. What's more the crack's overall path and shaping are rather too neat to be natural – more like a cartoon quake than a real outbreak of geological chaos. There is, in fact, a slightly dead-pan comic aspect to its sharp and zippy zig-zags.

But the thing about these amazing art spectacles, of course, is that neither the artist nor the art establishment will ever be content to let them be (what they are) just impressively amazing. That would be too much like fun and not enough like art. Even last year's helter-skelters, quite obviously a form of fun, were deemed also to engender a state of hysteria, loss of self, almost madness in the user – which, if true, is also true of any big white-knuckle ride in a theme-park.

No, the rule is: the bigger the spectacle, the more it's in danger of seeming simply a spectacle, the more inexpressibly significant it must be – in compensation, so to speak. And I can hardly tell you all the things that the crack in Tate Modern turns out to mean. But if you consult the accompanying Tate literature, you'll find it holds a real festival of the interpreter's art.

Take any thought that might be derived from free associating around the words: crack, fissure, cut, gash, wound, scar, gap, void, fracture, division, fault-line, damage, disaster, excavation, abyss or seismic shift. You'll find someone saying that this is what the work's about, with special reference to the "War on Terror", or neo-colonialism, or the social fabric of London, or museums. For example: "The scar that this Gargantuan work constitutes is, in the first place, a literal one: the trace of deep pain ... a tiny portion of a cut that really runs through the entire world."

Nor is the artist standing back. Her title, Shibboleth, refers to an Old Testament story about a password, a word one tribe can pronounce and another can't. In other words, she emphasises the "dividing-line" aspect of the crack. But don't let that cramp your style. What does she know?

But in a sense, a work like this really is a dividing line – it divides up its audience. On the one side, traditional arty types believe that things in art galleries should, at all events, mean something very serious. On the other, the new audiences are attracted first and foremost by an eye-boggling spectacle. And then there is the Tate itself, doing its best to stand astride the gap that it has opened up, keeping one foot firmly on either bank, trying hard not to do the splits or fall down the middle.

Doris Salcedo: a biography

Born in 1958 in Bogota, Colombia, Doris Salcedo is one of the leading sculptors of her generation. Her work, often involving furniture, is influenced by experiences from her home country. Her early work focused on the stories of those abducted and killed during its recent troubled history. Her 1992-1993 Atrabiliarios (Defiant) installation featured women's shoes, some belonging to victims. In 2002, she lowered 280 chairs down the façade of the Palace of Justice in Bogota as a tribute to those killed in a failed coup 17 years earlier. A year later, at the 8th Istanbul Biennial, she filled a derelict building plot with 1,500 wooden chairs, above, to evoke the armies of immigrants underpinning the economy. Shibboleth at Tate Modern is her first commission in Britain. Salcedo graduated in fine art from the Universidad Nacional de Colombia in 1980 and did a masters at New York University before returning to Bogota to teach.

Hall of fame

By Arifa Akbar

Carsten Höller

Test site. 10 October 2006 - 15 April 2007

This installation, described by the artist as a "playground for the body and the brain", comprised five slides, the longest of which stretched down from the Tate's fifth floor for 182ft . The outer spectacle of watching people enjoying themselves on the slides, and the inner, emotional experience of the participants attracted all kinds of people, many of them young.

Rachel Whiteread

Embankment. 11 October 2005 - 1 May 2006

The former Turner Prize winner created a structure made up of 14,000 casts of cardboard boxes, stacked together. The cardboard box theme had associations with the storage of intimate personal items and evoked the sense of mystery surrounding notions of what a sealed box might contain.

Bruce Nauman

Raw Materials. 12 October 2004 – 2 May 2005

Nauman's "sound sculpture" consisted of 22 audio recordings, ranging from repetitions of words such as "think" and "thank-you" to texts that were sung, and background "white noise". Voices were sinister or tender and melancholic. There was no visual component to the work and the Turbine Hall stood empty, except for the murmur of dissonant sounds.

Olafur Eliasson

The Weather Project. 16 October 2003 - 21 march 2004

Arguably the most memorable installation, Eliasson transformed every inch of the hall. Even the air was permeated with a fine mist of faint, cloud-like formations. The ceiling was covered with a mirror, so visitors could see their reflection. At the far end hung a large circular form made up of hundreds of mono-frequency orange bulbs. It could have been the sun.

Anish Kapoor

Marsyas. 9 October 2002 - 6 April 2003

The title referred to a satyr in Greek mythology who died a brutal death at the hands of the god Apollo. In form it was a long, sensuously curving, deep-red sculpture that stretched the full length of the hall and right up to the ceiling. It comprised three steel rings joined with a single span of PVC membrane, which Kapoor described as being "rather like a flayed skin".

Juan Muñoz

Double Bind. 12 June 2001 - 10 March 2002

The installation was divided into two parts: on the upper level of the hall visitors could see a patterned floor through which two elevators rose and descended, as if running in perpetual motion. Moving further into the lower space, it was apparent that the shafts above were dotted with a cast of sculpted figures.

Louise Bourgeois

I Do, I Undo, I Redo. 12 May 2000 - 26 November 2000

The work consisted of three steel towers, each around 30 feet high, which dominated the far, east end of the hall. A spiral staircase was built into one tower which visitors could climb to reach raised platform areas, envisaged by the artist as stages for "intimate and revelatory encounters between strangers and friends alike".