The Oceanário de Lisboa is a popular public aquarium and oceanarium located in Lisbon, Portugal.

It is one of the largest indoor aquariums in Europe and is known for its impressive marine life displays.

The Oceanário is situated in the Parque das Nações (Park of Nations), which is an area that was developed for the 1998 World Exposition (Expo '98).

The main attraction of the Oceanário is a massive central tank, which holds about 5 million liters of seawater and is designed to replicate the open ocean.

Visitors can walk through a transparent tunnel that runs through the tank, allowing them to observe various marine species, including sharks, rays, and a wide variety of fish, as if they were underwater.

In addition to the central tank, the Oceanário also has smaller tanks and exhibits showcasing different ecosystems and marine life from around the world, such as tropical and temperate coastal habitats.

It provides an educational and immersive experience, making it a popular destination for both tourists and locals interested in marine biology and ocean conservation.

The Oceanário de Lisboa plays an important role in promoting awareness of marine biodiversity and the need for conservation efforts to protect our oceans.

It also conducts research and educational programs to further its mission of preserving marine life and ecosystems.