Lake Hillier is a pink-colored lake located on Middle Island, one of the islands in the Recherche Archipelago off the south coast of Western Australia. The lake is surrounded by eucalyptus trees and is surrounded by sand dunes and woodland, with a narrow strip of land separating it from the nearby Pacific Ocean. The lake is well known for its unusual pink color, which is thought to be due to the presence of a high concentration of algae or bacteria in the water. Despite extensive research, the exact cause of the lake's unique color remains unknown, and it continues to captivate visitors from around the world.

Visitors to Lake Hillier can reach the lake by boat or by air, as there are regular flights over the Recherche Archipelago. The lake is part of the Recherche Archipelago Nature Reserve and is protected by the Western Australian government. Despite its remote location, Lake Hillier remains a popular tourist destination, and is widely considered to be one of the most unique and beautiful natural wonders in Australia.