Josef Gottschall's mind was in the gutter. Four years ago, he had just become publicity manager at Vienna's sewer company and was struggling for inspirations to promote it.
'Everything is below ground and your product is . . .' unmentionable, Mr. Gottschall says.
Fortunately, the classic 1949 film with Orson Welles, 'The Third Man,' climaxes in a dramatic chase through Vienna's sewers. Capitalizing on that, Mr. Gottschall launched a Third Man Tour of the subterranean waterways. Today, it's an underground hit.
Vienna isn't alone in plumbing the depths of tourism. A local chamber of commerce in Brighton, England, in 2007 voted the city's sewers the 'Best Place to Visit.' The living monument to Victorian engineering and architecture topped other attractions including the Duke of York's Picturehouse, one of Britain's oldest cinemas.
Brussels in 2007 renovated its sewer museum, whose exterior resembles a Greek temple. Underneath, visitors can stroll unaccompanied along a redolent sluiceway.
And the wellspring of sewer tourism, Paris's Musee des Egouts, plans a makeover to handle rising traffic, which surpasses 100,000 visitors a year.
Museum officials, who are all sewer workers, aim to expand their exhibits on topics including water treatment, safety equipment and unexpected discoveries.
One display in the spacious sewer tunnels celebrates notable items retrieved, including swords, stolen handbags and false teeth. Another commemorates Eleanor, a 32-inch alligator, whom workers caught in 1984 and who now lives in a Paris zoo.
Tours of the city's sewers, already famous from Victor Hugo's 'Les Miserables,' began in 1867, when a revolutionary, modernized network collected only rainwater. Workers clad in white guided visitors aboard special tour barges and wagons.
'It was very chic,' says museum spokeswoman Marie-Christine Amable. 'We had beautiful sewers.' Toilet waste came in 1894, but the rides continued for 80 years.
Sewer museum officials around Europe say they're flush with visitors now thanks in part to environmental concerns. People are increasingly curious about how their waste is handled. Water authorities are capitalizing on the attention to teach citizens they shouldn't do things like pour oil and grease down the drain.
'We can show the public what flows by in raw sewage,' says Brighton sewer tour guide Stuart Slark.
But celebrating effluent management poses unusual curatorial challenges. Constant moisture and noxious chemicals ruin displays. Heavy rains flood galleries. Deadly and explosive gases can build up, forcing hasty evacuations. Rats run rampant.
'It's not so easy to prepare the sewer for visitors,' says Mr. Gottschall in Vienna, an engineer who once designed sanitary works. 'The safety instruction book is like this,' he adds, holding his thumb and forefinger an inch apart.
But danger and noisome corridors don't deter tourists bored with churches and monuments.
'Everybody does the Arc de Triomphe,' said Harry Chlebos, a retiree from Phoenix, while examining the City of Light's dark underbelly. Older Americans know of Paris's sewers, he added, from a reference to them decades ago in an episode of 'The Honeymooners,' in which sewer worker Ed Norton dresses up as the man he claims designed them.
Young Americans are also attracted. Museum manager Lionel Decaix says that about five years ago, two young fans of 'Jackass' TV shows and films, which feature people doing foolish stunts and pranks, hid in the museum at closing to make an amateur video. They immediately tripped alarms and had to be released by the police. 'Americans are very intrepid,' says Mr. Decaix.
So is Brighton native Steve Sparks, who proposed to his girlfriend, Carolyn Payne, during a tour of the city's sewer last May. 'I was a little nervous about losing the ring,' recalls the property developer, who dropped to one knee inside a cavernous red-brick storm drain. Mr. Sparks, who coordinated his plans with sewer-operator Southern Water, says he wanted to make the moment unusual.
'I believe that since the sewers were built in 1870, nobody has proposed in them,' says Mr. Sparks, 42.
Despite Ms. Payne's shock, she said yes. 'It's really quite beautiful and cathedral-like there,' says the November bride, who is 30. 'It does still smell,' she adds.
Odor also can't deter lovers of 'The Third Man' from following Orson Welles's footsteps down a spiral brick staircase. The film, a dark thriller involving murder, smuggling and deceit in the rubble of occupied Vienna, has long drawn fans above ground.
Brigitte Timmermann, author of a 420-page tome called 'The Third Man's Vienna,' has led tours dedicated to the movie, written by novelist Graham Greene, in her native city for years. The Third Man Museum, an exhaustive collection of artifacts and memorabilia amassed by a Viennese couple, opened in 2005.
When Mr. Gottschall shifted to promoting sewers in 2007, he quickly got together with Ms. Timmermann's Vienna Walks & Talks and the museum to offer a whole package. They all were thrilled finally to link with the sewer.
For his part, Mr. Gottschall scrambled to secure rights to show three minutes of the movie. A bigger challenge was installing lights and projectors that would automatically disconnect if chemical sensors detected dangerous gases, including carbon monoxide, methane and sulfuric acid. Switches are similar to miners' equipment and don't cause sparks, as normal circuits can.
Underground today, visitors first see a film about Vienna's sanitation and the tasks sewer workers perform, projected on the wall of a spacious sewage-filtering chamber. Then they see clips from 'The Third Man' in a nearby chamber, where several chase scenes were filmed. Finally, visitors spill out into the vast, vaulted tunnel that channels the Vienna River and that provided a memorable setting in the film.
Tour guides note that many sewer scenes were actually shot on a dry, odor-free soundstage in London. Crossing Vienna's underground without soaking beautifully polished wingtips -- as Mr. Welles' character does -- would be impossible, they explain.
Ashley Venzel, a 26-year-old English teacher from Ohio, took the tour on a recent day after watching 'The Third Man' with her boyfriend. She enjoyed it partly because 'it's not very touristy,' she said while removing the spelunker's helmet that visitors must don.
Mr. Sparks, the Brighton newlywed, looks forward to touring other cities' sanitary works. Vienna sounds interesting, he says, but Paris is particularly romantic. 'Maybe Paris for our first anniversary,' he says.
Daniel Michaels