Initially named by Arab seafarers for its harsh environment, Aldabra became a French colony dependency in the 18th century, leading to the exploitation of its natural resources, particularly giant tortoises.

The atoll boasts unique geography, featuring the world's largest raised coral reef and a large shallow lagoon.

Post-World War II, conservation efforts increased, leading to its inclusion in the British Indian Ocean Territory and eventual independence for Seychelles.

Following an international protest by scientists known as the 'Aldabra Affair,' the Royal Society of London and later the Seychelles Islands Foundation conducted research, leading to Aldabra's declaration as a UNESCO World Heritage Site in 1982.

The atoll's flora and fauna, notably the giant tortoises, comprise an 'ecological wonder', with Aldabra serving as a critical breeding ground for various species.

Conservation challenges, such as invasive species and plastic pollution, persist, but protective measures, including UNESCO designation, underscore Aldabra's significance as a natural vital scientific research site.

In the middle of the 18th century, the atoll became a dependency of the French colony of Réunion, from where expeditions were made for the capture of the Aldabra giant tortoises.

After an international protest by scientists (known as 'the Aldabra Affair'),[13] however, the military plans were abandoned and the atoll instead received full protection.

[10] The "Environmental lobbyists" under the leadership of Julian Huxley, with the support of MPs Tam Dalyell and Robin Cook,[14] got the British venture torpedoed.

[15][16] In 1966, British Defence Minister Denis Healey had observed: "As I understand it, the island of Aldabra is inhabited - like Her Majesty's Opposition Front bench - by giant turtles, frigate birds and boobies.

"[17] Subsequent to the thwarting of plans to establish a military station at Aldabra (which instead focused on Diego Garcia in the Chagos Islands), the Royal Society of London resumed their scientific study of the flora and fauna of the atoll with Professor David Stoddart as the leader.

[9][17] SIF functions under the patronage of the President of Seychelles and Aldabra was declared a Special Nature Reserve in 1981; it became a UNESCO World Heritage Site on 19 November 1982.

A brass plaque inscribed with the citation "Aldabra, wonder of nature given to humanity by the people of the Republic of Seychelles" was erected on the atoll.

[25] The atoll consists of reef limestone of Pleistocene age (with irregular coral formations called "champignon",[26] made up of two layers of varying stages of crystallization [27]) and this extends over an average width of 2 kilometres (1.2 mi) rising to a height of 8 metres (26 ft) above sea level, and forming the rim line (low cliffs with "deep notches, preceded by jagged pinnacles") of the shallow central lagoon.

[7][27] While the terrestrial topography (spread over an elevation range of 0–8 metres (0–26 ft)[26]) is rugged and dictated by the geomorphic conditions, the land surface comprises limestone of about 125,000 years age, which has uplifted many times above the sea level.

The tropicbird orchid (Angraecum seychellarum) is the national flower of Seychelles and is found in the dry craggy limestone champignon of Aldabra.

[35] The lagoon is bordered by mangrove forests, and has large inland seagrass meadows as well as areas of coral reef and sand flats.

[7] The mangroves, which thrive in tidal mudflat areas and saline conditions, are seen on the shores of the lagoon and are integral to the coastal ecosystem.

[36] The atoll has distinctive fauna including the largest population of giant tortoises (Aldabrachelys gigantea) in the world (100,000 animals).

[12] One of the longest-lived Aldabra giant tortoises was Adwaita, a male who died at the age of about 250 years at Kolkata's Alipore Zoological Gardens on 24 March 2006.

[43] Endemic birds include the Aldabra drongo (Dicrurus aldabranus), the Aldabran subspecies of the white-throated rail (Dryolimnas cuvieri aldabranus), the last surviving flightless bird of the Indian Ocean region, and the endemic Aldabra fody (Foudia aldabrana),[26] The islands are important breeding grounds for thousands of seabirds, including several species of tern, red-tailed tropicbirds, white-tailed tropicbirds, red-footed boobies, and the world's second largest breeding populations of great and lesser frigate birds.

[39] Aldabra also accumulates large amounts of plastic pollution on its coastline and, despite a major clean-up effort in 2019, over 500 tonnes is thought to remain on the atoll, with significant impacts on wildlife.

[57] Most of this pollution originates from the regional fishing industry, although a significant proportion is also transported from southeast Asia through ocean currents.

[59] Fortunately, there are some signs of recovery, as the abundance of juvenile corals has since increased significantly, particularly within the lagoon,[60] although Aldabra's reefs of course remain critically threatened by climate change.

[7] Based on the evaluation process, UNESCO inscribed the site, a legally protected special reserve of 35,000 hectares (86,000 acres), on the list of World Heritage Sites under three criteria: Criterion (vii): Aldabra Atoll encompasses a large expanse of relatively untouched natural beauty where a number of important animal species and some plant species thrive, along with remarkable land formations, and its process provides a unique spectacle of natural phenomena;[7] Criterion (ix): The atoll is a superlative example of an oceanic island ecosystem in which evolutionary processes are active within a rich biota.

The size and morphological diversity of the atoll has permitted the development of a variety of discrete insular communities with a high incidence of endemicity among the constituent species that are typical of island ecosystems.

[17] Covering 25,100 ha (over half the area of the whole atoll) the wetland ecosystem of Aldabra includes the extensive shallow lagoon inside the atoll, which is carpeted with lush seagrass beds and patchy coral reefs, the intertidal mud flats, the coral reefs outside the lagoon, freshwater pools, beaches, and 2000 ha of mangrove stands.

Aldabra was designated as a site under the Indian Ocean South East Asia (IOSEA) turtle network, in their 2014 convention.

Visits to the island by people other than the scientists and staff of the SIF are strictly controlled and only guided tours are provided with prior permission.

Within the atoll, paved walking paths exist from the village of La Gigi, which leads to a promontory from where scenic views of the large lagoon (during low tides) and the mangrove species are seen.