A short cable car strung along the Tagus waterfront in Parque das Nações, running roughly a kilometre between the Oceanário and the Vasco da Gama Tower. The cabins rise high enough to give a clear view over the river, the Vasco da Gama Bridge, and the Expo 98 grounds below, and the ride takes only a few minutes each way.
It is more a pleasant diversion than a sight in its own right, best treated as a one-way ride to or from the marina end of the district. Tickets are sold for single or return trips; the views are the whole point, so pick a clear day.