Il-Maqluba is the best example of a deep, large-scale inland solution subsidence structure (doline) in the Maltese Islands. It is the only natural sub-circular depression that is not filled with sediment, owing to the relatively recent collapse of the limestone surface which formed the roof of a fairly large cave. The doline serves as a natural soak-away reservoir, with a depth of approximately 15 metres, an area of approximately 6,000m² and a perimeter of 300 metres. The doline is superimposed onto the main tributary of Wied Babu, which it divides into two (Wied San Mattew and Wied Ħal-Lew), thus adding to its uniqueness.
Il-Maqluba supports a dense maquis community dominated by Bay Laurel (Laurus nobilis) and a native stand of mature specimens of Malta’s National Tree: the Sandarac Gum Tree (Tetraclinis articulata). The area is also of significant scientific importance since it is the only known locality in the Maltese Islands for an undescribed species of endemic millipede and the ant Strumigens lewisi, a species of biogeographical interest. Malta’s National Bird, the Blue Rock Thrush (Monticola solitarius) is also known to breed at Il-Maqluba. The immediate surroundings of Il-Maqluba support a maquis dominated by Carob trees (Ceratonia siliqua) and Hawthorn (Crataegus monogyna) amongst several others.
MEPA scheduled Il-Maqluba as a Level 1 Area of Ecological Importance and a Level 1 Site of Scientific Importance as per Government Notice No. 1138/08 in the Government Gazette dated 19 December 2008.