The Chand Pol or the Moon Gate, which was the main gate of entry for the commoners. The upper storey of the gate is called the 'Naubatkhana' and housed the kettle drums and other musical instruments . Naubat was a type of music which had its own specific protocol that had to be strictly followed when it was played with, the listeners were expected to remain silent. It is believed that the tradition of playing the Naubat dates back to the time of Alexender the Great. [Wikipedia]