Months of torrential rain have wrought havoc with the building schedule, but the profile of Lisbon's Expo98, rising from the sludge and the clutter of heavy machinery, is now etched upon perhaps the finest river- front in Europe.
The landmarks of this 5km stretch of the Tagus estuary are not the pavilions that will house the efforts of 150 countries. These are, if anything, the least significant element, a slab of hangars supplied by the Portuguese hosts that will mostly be dismantled after the event.
Like Barcelona during the 1992 Olympics, and unlike Seville's Expo92, Lisbon recognised from the start that the international jamboree that opens on 22 May was a perfect excuse to resuscitate an ugly, stinking waste of space in the heart of the city. A slaughterhouse, a refuse tip and breaker's yard, an arms factory, a gasworks and an oil refinery were purged from the 840-acre site. Expo's authorities resolved that nearly all the new buildings would be permanent and would nourish a genuine urban community after exhibitors fold their tents.
This was a sideswipe at Seville's Expo, which for years after 1992 remained a forlorn wasteland pocked with weed-strewn concrete plots and abandoned pavilions. Only now, with a "magic island" adventure theme park and offices occupied by hi-tech multinationals, are the River Guadalquivir's reclaimed mudflats being used.
Lisbon, renowned for its sleepy charm, is being bounced into chaotic activity as the deadline looms. Torrential rains have caused huge delays, and prompted much official nailbiting. It is reckoned, however, that by working round the clock and taking a flexible view of the pounds 1.5bn budget, everything will open on time, except some carparks and a hotel.
Expo98's "Oceans" theme chimes with the 500th anniversary of Vasco da Gama's first sea passage to India and is, says Britain's Expo representative in Lisbon, Martyn Warr, more readily translatable into real exhibits than was Seville's abstract "Discoveries" theme. He promises the British pavilion will be a lively multimedia showcase for the latest marine technology, and insists Britain has learned from its dismal performance in Seville "where we spent far too much effort on the pavilion instead of what went inside it".
Europe's biggest oceanarium is being touted as the long-term symbol of Expo98. Designed by the American architect Peter Chermayeff who has been making aquariums since 1962, it is already stocked with fish and with birds and animals whose activities can be viewed both above water level and from the ocean floor.
"It is the centrepiece of the Expo, an institution for the study of nature that helps us understand the sea ... and it is a declaration about the fragility of the planet," Chermayeff said recently.
Most of the expected 10 million visitors will enter the Expo via the split level rail, metro and bus interchange designed by the Spanish architect Santiago Calatrava, an airy stylised forest of steel, concrete and glass. His splendid Oriente Station offers the most convincing indication that normal life will pervade the site after October. Some 10,000 homes, schools, hospitals and shops are part of the post-Expo plan, which includes a business district, marina and riverside gardens.
Other landmarks include the egg-shaped "Utopia" building whose curved wooden ceiling suggests the upturned hull of a ship; and the Portuguese Pavilion by the Portuguese architect Alvaro Siza Vieira that incorporates a thin concrete canopy hung like a sheet of paper over a plaza that looks across the estuary. It will display a permanent celebration of Portugal's relationship with the sea.
You get a stunning panorama of all this from the elegant new 18km bridge that threads like a necklace across the estuary's pearly waters. The British- built bridge that will link Lisbon to Spain and the Algarve is well on target to open with the Expo, a spokesman says. Last week workmen wired up the lampstands that tilt inwards, offering drivers a sense of protection from the vast expanse of water.
A rare naff note is the Expo's silly mascot, Gil, a nerdy Essoman with a wave-shaped head. And a 15,000-seat video stadium seems to have been an afterthought to boost attendance by screening matches of the World Cup.
I tore myself away from one of the Pacific habitat's tumbling otters and the potbellied penguins from Antarctica, and spotted a camera crew. They were filming a pair of glossy young men against the backdrop of scaffolding and the glinting estuary. "They're shooting a TV soap opera," said my guide shamefacedly. He should be proud. If Portugal's most adored art form has embraced the Expo, success seems guaranteed.