The Monterey Bay Aquarium is a public aquarium located in Monterey, California, United States. It was opened on October 20, 1984, and has since become one of the largest and most well-known aquariums in the world. The aquarium's mission is to inspire conservation of the ocean and its inhabitants, and to provide a window into the marine life of Monterey Bay and the Pacific Ocean.

The aquarium is home to over 35,000 animals representing more than 550 species. Among the many exhibits are the Kelp Forest, which replicates the ecosystem of a towering kelp forest; the Open Sea exhibit, featuring tuna, sharks, and other pelagic species; and the Sea Otter exhibit, which showcases the playful and charismatic marine mammals that were once hunted to near-extinction. The aquarium also has a sea turtle exhibit, jellyfish exhibit, and a large aviary featuring shorebirds.

One of the most popular attractions at the aquarium is the Outer Bay exhibit, which features a 1.2-million-gallon tank that houses tuna, sharks, sea turtles, and other large marine animals. Visitors can view the exhibit from a 90-foot-long viewing tunnel that passes through the center of the tank, or from a variety of other vantage points.

In addition to its exhibits, the Monterey Bay Aquarium is also involved in a variety of conservation and research initiatives. These include studying the impacts of climate change on the ocean, promoting sustainable seafood practices, and advocating for marine protected areas.