According to Untapped Cities, a website that explores New York City, these manhole covers generally weigh between 200 and 300 pounds (90 and 136 kilograms) and are made from concrete or cast iron.

Manhole covers are large cast-iron discs used to cover openings to the city’s gas, electrical, water and sewer lines. On average, they are about 3 feet in diameter and weigh about 300 pounds.

But what a cover. Two feet across, about two inches thick, solid cast iron. While there are other suppliers, many Chicago covers originate here, in the sprawling, loud Neenah Plant No. 2, the main ...

Dylan manhole covers cast in iron OK, Dylan fans, here's a pop quiz: Your job is to name the Bob Dylan song depicted on a manhole cover -- yes, we said manhole cover -- designed by Duluth artist ...

Calgarians will soon be walking, cycling and driving over much fancier manhole covers. The city is installing new circular cast iron slabs that illustrate the various liquids washing through more ...

The Collins Iron Works, where cast iron and steel were constantly being melted, was susceptible to fires. The foundry was destroyed and rebuilt after major blazes in 1923 and 1932.