The entrance of the Khyber Pass, 1910 (c)

Photograph, India, North West Frontier, 1910 (c).

The Khyber Pass is a 53-kilometer (33-miles) passage through the Hindu Kush. It connects the northern frontier of what is now Pakistan with Afghanistan. The British took control of the pass in 1849 following their annexation of the Punjab and North West Frontier.

Although the local Afridi tribesmen were often paid subsidies in the hope that they would allow military access to it, the British regularly launched punitive expeditions against them following their attacks on military convoys and trading caravans using the pass. This was especially true during the British incursions into Afghanistan in 1878 and 1919 when safeguarding the lines of communication through the Khyber was crucial.