Fol­low­ing his defeat of the Mughal emper­or Humayun in 1541, Sher Shah Suri built a strong for­ti­fied com­plex at Rohtas, a strate­gic site in the north of what is now Pak­istan. It was nev­er tak­en by storm and has sur­vived intact to the present day. The main for­ti­fi­ca­tions con­sist of the mas­sive walls, which extend for more than 4 km, they are lined with bas­tions and pierced by mon­u­men­tal gate­ways. Rohtas Fort, also called Qila Rohtas, is an excep­tion­al exam­ple of ear­ly Mus­lim mil­i­tary archi­tec­ture in Cen­tral and South Asia.