City dwellers walk over countless manhole covers every day, but how often do you stop to think about where these heavy metal disks in the streets come from?

Howrah, India is one of the world’s largest exporters of sanitary castings, like grates and manhole covers. Filmmaker Natasha Raheja went to one of these factories to see how these ubiquitous features of streetscapes half a world away get fashioned. Feet play a bigger role here than you might imagine. 

[h/t: Gizmodo]

Banner image screenshot via YouTube