In the late 1800s, the Victorian Government devised a coastal defence network for Port Phillip in response to the fear of attack and invasion from foreign enemies during the Victorian gold rush. One of the critical components of this defence network was Pope's Eye, an island fort intended to defend the entrance to Port Phillip. This semicircular, horse-shoe-shaped ring of large basalt blocks was never completed as a fort, but it still serves as a protected nesting ground for the Australasian Gannets.

Located in Port Phillip Bay, Pope's Eye has become a top spot for snorkelling and diving with its tropical reef-like appearance. The inside of the "eye" is only about 2 m deep, showcasing a beautiful azure blue with a soft, sandy bottom. Named after a naval midshipman, the fort has been protected as a marine reserve since 1979 and is now part of the Port Phillip Heads Marine National Park.

The resident colony of Australasian Gannets builds their nests from seaweeds and guano and rear their chicks on the platform. These large seabirds are plunge divers and can be seen spectacularly diving into the water to catch their prey. Pope's Eye's protection from tidal currents supports various species, including colourful reef fish, octopus, featherstars, cuttlefish, seals, and gorgonian corals.

Despite never being fully completed as a fort, Pope's Eye still holds an important place in the history of the coastal defence of Port Phillip. Today, it is an important ecological site and a must-see destination for nature enthusiasts and divers. The protection and preservation of this unique island fort ensure that it will continue to be a valuable asset for future generations.