Surya kiran when the people can build bridges now why can't people build bridges before. do you think only the present man is intelligent.
You will laugh if I say there were aeroplanes during the period of rama. There are ancient texts on that. Vimanasatra an ancient text is available in The library of ISRO ( SHAR) also withh one of the Aeronautical profs at IIT Madras as per my knowledge. there may be some more copies also. Even it translation is availble. U Google for and then comment.
Did u read the previous interious of eminent people in rediff. They wer cleary stating that the material of the bridge is same from top to bottom, which states that it is made from same material, If it is anatural formation it takes thousands of yars to form a structure like that and it would be in layers and layers of different materials
