In 1957 the government agreed to temporarily reserve a 22-mile (35 km) stretch of the Exuma cays, providing that some group would explore the possibility of creating a national park and make concrete recommendations.
Allen and other well-known conservationists, including Donald Squires of the American Museum of Natural History and Bahamian experts Oris Russell and Herbert McKinney, were part of the team.
They spent a week travelling by boat from Norman's Cay to Conch Cut and their report led to the creation of the world's first land and sea park in the Exumas, as well as to the formation of the Bahamas National Trust itself.
The government adopted the expedition's recommendations wholesale and the 176-square-mile (460 km2) Exuma Cays Land and Sea Park, the first of its kind in the world, was officially established, and The Bahamas National Trust was created as an independent statutory organization charged with conservation and preservation.
In addition to overseeing the Exuma Cays Land and Sea Park, The Bahamas National Trust also took over responsibility for the endangered flamingos on Inagua.