Nearby is the so-called "iron pillar of Delhi," built by Gupta emperor Chandragupta II in 402 at a Hindu temple in Vidisha (south of here), and moved to its present location in the 10th century by Tomar emperor Anangpal. It does what it says on the tin, but is actually much more impressive than it seems. You see, it has withstood rust for all that time, a testament to the proficiency of ancient Indian metallurgy. This is the only thing in the world from that time known to resist rust.