Santa Monica Pier Aquarium, Marine education center beneath Santa Monica Pier, California, US.

The Santa Monica Pier Aquarium is a marine education facility located beneath the famous pier on California's coast. It displays over 100 species of marine animals from Santa Monica Bay, including leopard sharks and moray eels, in a compact underground space.

The facility opened as the Ocean Discovery Center and was run by UCLA until 2003, when Heal the Bay, a nonprofit, took over operations. It now serves as Heal the Bay's marine education, advocacy and community science facility, with programs on marine conservation, pollution prevention and environmental education.

The name comes from Heal the Bay, the nonprofit that has run the facility since 2003; it was previously the Ocean Discovery Center under UCLA. Staff and volunteers lead school groups and community science projects on marine conservation and pollution prevention, and about 15,000 of the roughly 100,000 yearly visitors are students.

The aquarium sits in the sand beneath the Santa Monica Pier, next to the Pacific Ocean, within a California State Beach park run by the Los Angeles County Department of Beaches and Harbors. Look for the entrance at pier level below the deck. The exhibit hall is compact and dim, so allow time to move through it with children.

A two-spotted octopus caused an unexpected flood in 2009 by manipulating a drainage valve in its tank. The incident showed just how intelligent these animals are and how they explore and alter their surroundings.