Golkonda fort is one of the most famous and the biggest fortress in the Deccan plateau of India. Built on a 400 ft. high hill with a circumference of 7 km of the fort wall containing 8 gates and 87 bastions each 50-60 feet high. There is a ditch around the outer fortified wall. All the bastions are mounted with heavy cannons, rendering the fort one of the shongest of the medieval forts of the Deccan. The fort has three lines of powerful fortification walls one within the other. The first line encloses the town, the second a double wall, runs around the foot of the hill on which the citadel stands. The third line within the second and further up the hill is formed by connecting walls of masonry to the natural boulders. An extension of the outer wall was made to enclose a small area on the north-east of the town in 1,724 AD now known as Naya Qila. The fort has a striking appearance and its higher area is covered with the remains of armouries, magazines, mosques, granaries, reservoirs and audience chambers; while at the foot of the citadel nestled the erstwhile dwellings of the queens and princesses and homesteads of their retainers.
Outer fortification wall:
The outer fortification wall varies in thickness from 5 m to 10 m. It has a battered plinth which in some places rises in barrel shape from bottom to the full height of the wall. This is further strengthened at short intervals by large bastions, one of which is at the north-west called Petla Burj. Another in the north-west called a nine lobed bastion was built with a corrugated face with nine lobes, which provides greater length to the parapet for defence and greater facilities to the fire in all directions from the battlements.
There are eight gates in the outer fortification wall, the Fateh, Bahmani, Mecca, Patancheru, Banjara, Jamali, Naya Qula and Moti. Among these only four gates are wall known i.e. Fateh, Mecca, Banjara and Jamali. All these gates are entered through a sinuous barbican composed of two huge wings jutting out from the walls with crenellated and box machicolations for deLence. At various places vent-holes pointing directly downwards to command the foot way immediately below, by firing. All these gates were provided with two leated doors of teak which were covered with iron sheets and studded with sharp spikes. The spikes are dispersed well over the door to guard against elephant attacks.
A remarkable signalling device was incorporated in Golkonda fort's construction. The various edifices are so placed as to transmit sound to different far away points. If one claps standing at the centre of the entrance portal the sound is deflected by the opposite building which is constructed at an angle to the entrance. Similarly if a clapping sound is made from the opposite building, that sound will carry to the hill-top although at other close points it may not be heard at all.