Gol Gumbaz ( Urdu: گول گمبد)is the mausoleum of Mohammed Adil Shah (1627-55) of the Adil Shahi dynasty of Indian sultans, who ruled the Sultanate of Bijapur from 1490 to 1686. The tomb, located in the city of Bijapur, or Vijapur in Karnataka, southern India, was built in 1659 by the famous architect, Yaqut of Dabul. The structure consists of a massive square chamber measuring nearly 50 m (160 ft) on each side and covered by a huge dome 43.3 m (142 ft) in diameter making it among one of the largest dome structures in world. The dome is supported on giant squinches supported by groined pendentives while outside the building is supported by domed octagonal corner towers. The Dome is the second largest one in the world which is unsupported by any pillars. The acoustics of the enclosed place make it a whispering gallery where even the smallest sound is heard across the other side of the Gumbaz. At the periphery of the dome is a circular balcony where visitors can witness the astounding whispering gallery. Any whisper, clap or sound gets echoed around 7 times. Anything whispered from one corner of the gallery can be heard clearly on the diagonally opposite side. It is also said that the Sultan, Ibrahim Adil Shah and his Queen used to converse in the same manner. During his time, the musicians used to sing, seated in the whispering gallery so that the sound produced could reach every corner of the hall. Right below the whispering gallery, in the hall the dancers provided entertainment. Each tower consists of seven storeys and the upper floor of each opens on to a round gallery which surrounds the dome. In the centre of the chamber is a square raised podium approached by steps in the centre of each side. In the centre of the podium are the tombs of Muhammad Adil Shah II and his relations. To the west of the podium in a large apse-like projection is the mosque, also raised slightly above the floor level of the chamber. Gol Gumbaz Circa 1860 Henry Hinton, a photographer from Britain was one of the first to record the splendid beauty of Gol Gumbaz. He mentions in Print 1 of The Ruins of Beejapoor, in a series of nineteen views from collodion negatives (Bombay, 1860). "…built on a terrace 200 yards square. Height of tomb externally 198 ft, internally 175. Diameter of dome 124 feet, 4 minarets of 8 storeys, 12 ft broad entered by winding staircases terminating in cupolas'. The Gol Gumbaz, a grand mausoleum of Muhammad Adil Shah, though a structural triumph of Deccan architecture, is impressively simple in design, with a hemispherical dome, nearly 44 mts in external diameter, resting on a cubical volume measuring 47.5 mts on each side. The dome is supported internally by eight intersecting arches created by two rotated squares that create interlocking pendentives. A cenotaph slab in the floor marks the true grave in the basement, the only instance of this practice in Adil Shahi architecture."