Jhulta Minar
Situated in Ahmedabad, Gujarat, Jhulta Minar is actually a part of the mosque Siddi Bashir.
Exisiting since 1452, it is believed that the mosque was constructed by Sidi Bashir, a slave of Sultan Ahmed Shah, while according to another belief the mosque was built by Malik Sarang, a noble in the court of Muhammed Begada.
While the entire building was destroyed during the war between the Marathas and Khan of Gujarat Sultanate in 1753, only the minarets and arched central gateway is left.
A traditional example of marvelous craftsmanship and architecture, the minars constructed in such a way hat, if you apply a little force on its upper arc, the Minar tends to sway. A minor shaking of either of the minaret results in the other minaret vibrating after a few seconds, though the connecting passage between them remains free of vibration.
While the reason is still unknown behind the swaying of the minarets, an Englishman did make an attempt to demolish one of the minarets of the mosque to find out the mystery, but failed