In the Qutb complex, within Delhi, is a 7 meter tall column. This giant pillar was thought to have originally come from a monarch in northern India back in 402 CE, but no one really knows for sure. What they do know is that it’s made completely of iron, but in over 1,600 years, it’s never shown a speck of rust.

Some scientists say its on account of the mild climate in Delhi, while others think that it’s the absence of sulphur and manganese in the make up. What’s also a head-scratcher is that no one knows how the column was forge-welded to even make it.