Photograph of Fort Onslow in Bimaru, taken by the Bengal Sappers and Miners, an engineering arm of the Indian Army in c.1879. Fort Onslow was situated on a range of hills due west of Kabul in Afghanistan. In the 19th century the British were engaged in military conflicts with Afghanistan due to British fear of Russian encroachment on their Indian colony and internal divisions within Afghanistan. During the Second Anglo-Afghan War (1878-80) British forces commanded by General Roberts occupied the area around Kabul and endeavoured to gain control of the imposing hills around the city. An extensive programme of defensive works was begun which included a trench wall along the Bimaru Heights, additional fortifications and new roads for the transportation of artillery. After a series of conflicts the British withdrew from the area in 1880.