Hankley Common is an area of heathland with sandy infertile soil. The dry areas are, for the most part, covered in common heather (Calluna vulgaris) and bell heather (Erica cinerea). There are patches of bracken (Pteridium aquilinum)
Hankley Common is a designated a Site of Special Scientific Interest (SSSI).
D-Day training sites were created in Britain in order to practice for Operation Overlord, the invasion of Northern France by allied forces in 1944.
In 1943, in an area of the common known as the Lion's Mouth, Canadian troops constructed a replica of a section of the Atlantic Wall. It is constructed from reinforced concrete and was used as a major training aid to develop and practise techniques to breach the defences of the French coast prior to the D-Day landings.
The wall is about 100 m long, 3m high by 3.5m wide. It is divided into two sections between which there were originally huge steel gates. Nearby are other obstacles such as dragon's teeth, huge reinforced concrete blocks and lengths of railway track set in concrete and wire entanglements. Much of the relics show clear signs of live weapons training and the main wall has two huge breaches caused by a variety of demolition devices including the Double Onion: a specialised demolition vehicle, one of Hobart's Funnies, based on the Churchill tank.
The reinforced concrete was made with thick rebars varying from 10 to 20 mm thick.
Over the years the wall has become colonised by alkaline-loving lichens, mosses, ferns and other plants because the concrete provides the lime-based substrate that these species require and which is found nowhere else in the locality. They present an unusual range of plants to be found in an expanse of acid heathland.
The preservation of the Wall is managed by Army Training Estates with the assistance of the MOD Hankley Conservation Group.
In 1942, Hankley Common was the site of a murder. The victim was a woman who was living rough in a crude shelter made of tree branches, and so the newspapers gave her the nickname of "Wigwam Girl" (it was then a commonplace error to use the term wigwam to refer to what is more properly known as a teepee). She was eventually identified as Joan Pearl Wolfe.
On 7 October 1942, two soldiers noticed an arm protruding from a shallow grave. On inspection, the badly decomposed body of a fully-clothed woman was found. A pathologist concluded that the woman had been stabbed with a hooked-tipped knife, but that the cause of death was a heavy blunt instrument and that the attack had occurred elsewhere. A police search of the common turned up the dead woman's Identity Card and a letter to a Canadian soldier called August Sangret who was of North American Indian ethnic origin. The letter informed Sangret that she was pregnant. When the police interviewed Sangret, he admitted having intimate relations with the girl and living with her in a tree wigwam. A heavy birch branch, with blood stains, was found near the grave and blood stains were found on Sangret's recently washed battledress. Later, a hooked-tip knife was found blocking a waste pipe.
Sangret was charged with Wolfe's murder, he was tried and convicted in February 1943. The jury who took two hours to reach their verdict made a strong recommendation to mercy. Before sentence of death was passed Sangret declared: "I am not guilty. I never killed that girl. Sanget's appeal was dismissed and he was hanged at Wandsworth Prison on 29 April 1943.
In the fourth series of Ultimate Force, the Drop Zone huts and surrounding area were used to shoot a Columbian forces training camp.