Just below Alfama, Lisbon's old Moorish quarter, with its incredibly narrow, steeply inclined streets - the kind of streets, indeed, that would give most road engineers a nightmare - four cruise ships with nothing better to do are moored for the summer to provide overflow accommodation for the crowds of tourists visiting Expo `98.
Lisbon hasn't got enough hotel rooms, so the cruise ships are a pragmatic response - and also quite appropriate, given that the Expo has a maritime theme and the Portuguese have such a rich history of navigating the oceans; they are also using the last universal exposition of the 20th century to remind us that they discovered half the world.
At the Expo, not surprisingly, Portugal's pavilion is by far the largest. The style is stripped-down neo-classical, curiously reminiscent of Mussolini's EUR centre in Rome, as if Salazar was still in power. Its piece de resistance is a concave reinforced concrete canopy, with a span of more than 50 metres, which is held up as if by magic.
Inside, the inscription over the set of doors leading into the main exhibit reads: "The Portuguese revealed the oceans to humankind . . . The oceans are in danger . . . Humankind must take care of the oceans." Inside, a multi-screen presentation concentrates on telling us all about the exploits of Vasco da Gama and other Portuguese explorers.
Japan discovered
The Japanese, too, have tailored their pavilion to take account of this theme. Without a hint of irony, they tell us how Japan was "discovered" by the Portuguese in the early 16th century. The Japanese, of course, always knew it was there; the adventurers from Lisbon merely stumbled upon it, gaining little more than a footnote in the country's history.
All of Portugal's former colonies, with the exception of Angola, are represented at Expo `98 - including the "Non Self-Governing Territory" of East Timor, which probably explains the absence of Indonesia. Macao has its very own free-standing pavilion, obviously a lavish last fling before being handed back to China next year.
The Pavilion of the Future picks up the oceanic theme, with a truly fantastic 3-D cinematic presentation, which has visitors queueing for an hour or more. The three-dimensional effects are so extraordinary that kids in a huge raked theatre at the heart of the pavilion reach out with their hands in a vain effort to grab some of the images.
Queues form outside many of the national exhibitions, notably those of Spain, Mexico and the USA. But they're minuscule compared to the vast crowd of people standing patiently in line under hastily-erected canopies outside the Oceanarium waiting to see - no, experience - the most spectacular collection of marine life ever seen anywhere.
Designed by Peter Chermayeff, a British-born architect of Russian origin who is based in Boston, Massachusetts, this mesmerising display has inevitably become the star attraction of Expo `98. The scale alone is staggering, with a main tank containing over four million litres of water - enough to fill five Olympic-size swimming pools.
Throngs of visitors are processed through dark passages, past transparent acrylic walls 36 centimetres thick, through which they can see a whole marine habitat contained in a tank fully two storeys high, with everything from small sharks and sea otters to sting rays and shoals of mackerel. As Time magazine enthused, it's an "indoor ocean".
Say less
"We have gone to great lengths to suppress the architecture", said Mr Chermayeff, whose firm - Cambridge Seven Associates - has designed more than a few aquariums around the world. "The departure with this aquarium is to say less and let people feel more." The effect is almost like being a deep-sea diver with your clothes on.
There's also a series of smaller tanks depicting ocean life from the tropics, with coral reefs and their lushly beautiful creatures, to the Antarctic, with penguins to beat the band. Altogether, the Oceanarium now provides a home for 8,000 inhabitants, and they all have to be fed - particularly the sharks, which can't be left to their own devices.
Another big draw at Expo `98 is the Virtual Reality Pavilion, where its designers clearly had a field day exploiting modern technology to create yet more special effects. And no visitor needs to fear going hungry - there are numerous restaurants on the site, representing the cuisine of countless countries - right down to stands selling hot dogs and cola.
Admission to the 330-hectare Expo site is a mere 1,500 escudos (less than £6) per day, which makes it considerably cheaper than Disneyland. And to help visitors get around, there's a bus service from one end of the site to the other as well as cable cars offering panoramic views. Seriously sedentary folk can even hire electric-powered buggies.
Cruise ship
Yet, the organisation still leaves a lot to be desired. Those attending a recent EU-sponsored symposium on "The City of Tomorrow" were all told that they would be accommodated on a four-star cruise ship, SS Sapphire Seas, moored in Lisbon harbour, and that there would be meeters and greeters at the airport to arrange transportation.
With no sign of any welcoming party, I decided to take a taxi, telling the driver that I wanted to go to a ship called Sapphire Seas in the city's docks. Much as we tried, we couldn't find it anywhere; the port authority even told us that there was no record of a ship by that name moored anywhere in Lisbon. Had it simply disappeared?
An hour later, after running up a fare of 4,000 escudos (£15.50), I was informed by an EU official that the name of the ship had been changed to Ocean Explorer I - but nobody in Lisbon thought of telling anyone in Brussels about it. We concluded that the Portuguese, even if they did discover half the world, couldn't organise a knees-up in a brewery.
And beware, too, of the use of the phrase "four-star". The Greek-owned, Liberia-registered Ocean Explorer I (ex-Sapphire Seas, in small print) is quite shabby, yet its cheapest rate is 120 dollars a night for an "inside cabin" - euphemism for a windowless room, with a loo that takes in polluted water from the Tagus to perform its function. But Lisbon remains a wonderful city. Though it seems to be shunned by most Irish tourists bound for Portugal - just as Ireland itself, disgracefully, declined to participate in Expo `98 - it really is well worth a visit, not least because it has none of the swaggering "high design" pretentions of Barcelona. Lisbon simply exists, as it always has.