On the northeastern riverfront lies the Parque das Nações. Built for Expo 98, the development includes a huge world-of-its-own aquarium, the Oceanário, plus the Pavilhão do Conhecimento, and a landscaped riverside park with restaurants and bars. There's some stunning modern architecture here: the ribbed Death Star structure of Gare do Oriente and the Pavilhão de Portugal by Portugal's leading architect, Álvaro Siza Vieira.
A riverside teleférico, more than 0.6 miles (1 kilometer) long and 66 ft (20 m) high, gives stunning views of the river and the Vasco da Gama bridge. The 1.2 mi (2 km) long park site sometimes feels as if you have wandered into an architectural model, but it's an entertaining place to visit, particularly for families. A mini-train trundles around hourly, and you can even rent bikes.
Take the metro to Gare do Oriente and walk through the Centro Vasco da Gama to the park's main Posto de Informação, with free maps and information. The Cartão do Parque gives admission to the Oceanário, Pavilhão do Conhecimento, cable car and Vasco da Gama tower, as well as some restaurant discounts.