Thanks for the overwhelming responses to the riddle. Yes, these are the ruins found around the Qutub Minar and the famous Iron Pillar in Delhi.
However not much is clear about them, though as Ragu mentioned there are various versions of pillaged temples, forts, jaina structures - Thomar, Rajput including as per the ASI board the original fort of Prithivraj Chauhan. Without going into those details, am sure a google search will land you on the various versions - incl a popular version in Amar Chitra Katha - for though the sights are visibly disturbing - the idea of presenting these was not to rake up any religious / communal sentiment. For that matter, everyday we are witnessing vandalism of our living temples even today, so why harbor hatred for something that happened hundred of years ago. There are thousands of such structures which you can adopt and safe in our rich country. Well, while i say that - as a art lover, you feel for the loss of the art and the effort of the sculptor. All is fair in war and conquest. But i would like to spur some creative outcome from this.
Lets go back and relook at the pillars for stylistic parallels. The sheer weight of these pillars could have made transportation over long distances tedious So they must have been from around Delhi of yore. But the artistic styling is quite unique, especially the Ganas supporting the roof at the top of the pillars, the floral designs on them.
The differently styled pillars also support the idea of their source from multiple places - you see some are very ornately carved, while others are without much embellishments. Can we spot parallels among other sites.