Imagine London without the Tube, New York without its subway or Paris without the Metro. The respective loss to each city would not just bring about travel chaos - it would be felt much deeper than that. For each system forms that city's network of veins. They shuttle residents around, carry tourists to and from travel hubs and famous landmarks and pull a city together. There are more than 160 "rapid transit systems" across the world, as they are known in the business. From Buenos Aires to Prague, Cairo to Seoul and now in Dubai, they spread their tentacles above and below ground across city landscapes. London is the world's oldest and largest, having opened in 1863 and now spread across 258 miles; Tokyo is the busiest, having carried 3.2 billion people last year; Montreal's is quite possibly the quietest, because it runs on rubber wheels.
Consequently, it is little wonder that metro systems have not only established a firm footing in popular culture - celebrated in books, films, artworks and music - but are often decorated cultural hubs themselves. From Marilyn Monroe's famous ventilation-grate scene in The Seven Year Itch, to Holden Caulfield's subway riding in The Catcher in The Rye via The Jam's Going Underground, there are thousands of examples. Here we select the best among them and look forward to the day that the Dubai Metro inspires its very own.
We're not talking about irritating beats escaping from someone's iPod headphones here, but busking - often a glorious element to any journey by tube, metro or subway. The violin strings of a classical piece might reach you while you sink down an escalator; somewhere a guitarist will be plonking away through Hotel California; an accordionist will quite probably have accosted you on the train itself with a proffered cap.
In London, busking was technically illegal until 2003 when a panel was set up to organise the system. Now, more than 300 official buskers play through 2,000 hours of music a week on 35 stages at 23 stations. In Paris, the busking situation is handled with immense care. The RATP, or the Paris metro system, has held biannual auditions for 250-300 licences since 1997. Hopeful applicants must play in front a panel, including representatives from the RATP, and their performances are videotaped before being shared with other RATP workers, Pop Idol-style. Only one in three applicants will make the cut, but even then they face rules before they can pick up their instrument of choice. All must buy a ticket for the spot at their station, all must be dressed decently and there must be no powerful amplifiers.
Busking has also acted as the launchpad for many a career - Bob Dylan, Edith Piaf and Tracy Chapman all spent time singing in stations. Correspondingly, commuters in cities across the world have previously had the fortune to unwittingly hear great talents strumming in unusual spots. In 1984, Paul McCartney donned a fake beard and dark glasses at London's Leicester Square station to play with his guitar. "I got a few shillings," he said afterwards, but handed them over to charity. In 2007, the classical violinist Joshua Bell busked at L'Enfant Plaza station in Washington, DC, using a Stradivarius violin worth $2 million (Dh7.35m). Of the 1097 people that went by in 45 minutes, only one recognised him and he made $32 (Dh118). Honorary mention goes to The Jam too, whose love for the London Underground brought forth not one but two tracks referring to it: Going Underground and Down in the Tube Station at Midnight.
Is it unfair to say how unlikely it seems that the world's most artistic metro system can be found in Sweden? At any rate, Stockholm's "tunnelbana" is often feted as the longest art exhibition in the world, running 110 kilometres in total, with 90 of 100 stations decorated with a variety of mosaics, installations, sculptures and paintings. Many stations have also been left as painted rock caverns, creating a uniquely underground feel. It is a creation of which the city is proud and, consequently, any trains that are besmirched with graffiti are taken out of service instantly.
Architecturally speaking, Moscow's metro system beats all comers. Created during the Stalinist regime, it opened in 1935. The stations were intended to be "palaces for the people", and many have marble-clad walls and chandelier lighting. Statues of past leaders stand proud in many and, earlier this week, a controversial decision was made to restore decorative adornments to Kurskaya station that read: "Stalin reared us on loyalty to the people. He inspired us to labour and heroism." Another proclaims "For the Motherland! For Stalin!" Dmitry Gaev, the head of the Moscow metro, has refuted all criticism, saying they only intend to restore stations to their former glory.
Paris is another city lauded for its artistic metro stations, and in particular for its distinctive Art Nouveau entrances designed by Hector Guimard and erected between 1899 and 1905. They are part of the Parisian landscape, with 88 of them remaining across the city. More recently, in 2000 the Palais Royal - Musée du Louvre station updated the look with a new entrance on Place Colette. Designed by the French artist Jean-Michel Othoniel, it is fashioned from multicoloured glass beads threaded around an aluminium frame.
Mention of course must also go to London, for being the first of the world's metro systems to have a corporate design. Its distinct logo, originally designed by Frank Pick in 1908, and its map, created by Henry Beck in 1931. The map in particular has spawned innumerable copycat pieces of artwork, several of which have become celebrated in their own right. In 1986, David Booth created a colourful version where the lines were squeezed out by tubes of paint; in 1992, Simon Patterson created a piece called The Great Bear by removing the names of tube stops and replacing them with scientists, philosophers and footballers.
Athens has a particularly fitting metro system given the age of the ancient city. There, Akropoli station has replica friezes from the Parthenon. Other stations have busts, pots and all manner of archaeological discoveries on display in them as if museums. Meanwhile, Brussels's Stockel metro stop merits a mention too, because it honours that beloved Belgian creation, Tintin. Along its 135- metre wall are images of all 140 characters of the cartoon series, drawn by Hergé himself and completed just before his death in 1983.
Movies, music videos, television series and advertisements have utilised metro stations the world over. Most recently, the New York subway has been in the news thanks to a suggested Michael Jackson commemoration. Fans have demanded that Brooklyn's Hoyt-Schermerhorn station, where Martin Scorsese directed the 1987 video for the song Bad, be renamed after him. The New York MTA (Metropolitan Transport Authority) is so far resisting these calls.
One of the greatest on-screen chase scenes in history is said to be between car and subway in the 1971 film The French Connection. Ghost, Superman, Saturday Night Fever, Die Hard: With a Vengeance and Midnight Cowboy all have key scenes and shots taken down there, as have hundreds of others. The 1974 film The Taking of Pelham One Two Three, set entirely on a subway train taken hostage, has just been remade, starring John Travolta and Denzel Washington.
London, too, has enjoyed its fair share of filming. The entire dual plotline of the 1998 film Sliding Doors, hinged on whether Gwyneth Paltrow's character caught a particular Tube or not. The disused station of Aldwych is also a favourite for filmmakers. The Krays, Patriot Games, V for Vendetta, Atonement and the BBC series Spooks have all made good use of its closure for scenes. According to the RTA, costs start at £300 (Dh1,810) per hour and can rise to £1,000 (Dh6,000) per hour depending on the scale of the project.
Toronto's metro has a similarly secret station used both for training of staff and filming. Called Lower Bay, underneath the operational Bay station between Bloor Street and Yorkville Avenue, most Toronto residents don't even know it exists. And yet Gene Hackman and Hugh Grant filmed the medical thriller Extreme Measures there, and Keanu Reeves, who grew up in the neighbourhood, used the station for part of his much-panned Johnny Mnemonic. Bollywood has also started to make great use of the Delhi Metro, which began operating in 2002. Surely the elevated sections of the Dubai Metro would make for a classic chase along the Sheikh Zayed Road?
Metro journeys are, of course, the perfect place for a quick read. Londonders often have their day brightened by the tube network's Poems on the Underground series, an initiative started in 1986 which posts poems old and new on tube carriages, between advertisements. The creation of the American writer Judith Chernaik, she continues to meet two other poets, Cicely Herbert and Gerard Benson, to discuss the next batch of work, which changes three times a year.
Back in Paris, the station for St-Germain-des-Pres is the only one in the network of 300 which doesn't have billboards. Instead, extracts from great French texts are projected on to the white-tiled walls. Similarly, at Cluny la Sorbonne, the ceiling there is plastered in mosaics celebrating writers such as Racine, Victor Hugo and Rimbaud. Subways and metros have been the stuff of novels and poems too. Stations are often the perfect setting for mystery, horror or intrigue. The poet John Betjeman previously wrote a short piece of prose about a London station, called South Kentish Town in which a passenger became trapped in the disused station. Agatha Christie's The Man in the Brown Suit starts off with a murder at Hyde Park Corner. And earlier this year, John Wray published his third novel, Lowboy, about a schizophrenic teenager with an unhealthy fixation on the New York subway. The first successful work from the French author Raymond Queneau was Zazie in the Metro, about a young girl who dodges the watchful eye of her Uncle and scarpers across Paris on her own. And most family-friendly of all, the headmaster of Hogwarts in the Harry Potter series, Albus Dumbledore, has a scar of the London underground map on his knee, though JK Rowling has never revealed why.
New Yorkers are so fond of reading on their subway that in July this year a reading scheme was set up. Called Choose What You Read, it is aimed at combatting the love of small screens - on iPods, video consoles and netbooks - it operates as a free service run by volunteers. On the first Tuesday of every month, boxes are placed at the biggest subway stations for people to drop literary offerings into, which can then be picked up by someone else. "We only ask that you return it once you are done so that the same book can be enjoyed by another commuter," they say.