My edition of the Rough Guide is the last one in which Expo 98 lies in the future and by the time I reached the Oceanarium it was in the past.
To an outsider like me, who had not seen Lisbon before, it would seem that the Expo's effects have been wholly for the good, making truly modern attractions, of which the splendid Oceanarium is only one, on a site which apparently was pretty dire before the expo and NOT spoiling the ancient historical attractions of the city one bit.
When I went, some of the pavilions that are going to be used again were not yet ready but there was another large pavilion with information on the world's oceans, a chair lift right along the site and and some good outdoor garden scenery.
How to describe the Oceanarium itself? I'll start by saying that I have since visited what was previously called one of the foremost aquaria (aquariums?) in Europe and, whilst I enjoyed it, it seemed like a museum in comparison.
The easy part is to say that it is very big and round and that it is entered by a high passage which can be accessed by a lift. Basically you walk for a vast distance at different levels, connected by lift or stairs around a massive tank - so massive that you only know by reason, never by sight, that you are seeing the same water. The fish come very close but they also swim far away so that there is an ever-changing piscatorial scene close to you. This is, as it were, on the inside of you. On the outside are largely open areas to give four separate areas recreating the environments of different parts of the world's oceans. These include non-aquatic mammals - though of course it is those that spend a lot of time in the water like otters - as well as seals and penguins.
I assume there are sights of this kind on the other side of the Atlantic but I have never seen anything remotely like it in Europe.