What innovation or invention made suspension bridges possible?

Several strands of metal twisted creating a durable string, that's the "wire rope", made of high carbon steel, and galvanized to improve corrosion resistance; a key structure together with "the web truss" when it comes to assembling suspension bridges;

but "The Bessemer process" was the fundamental industrial method for manufacturing and mass production of steel, invented by English engineer Sir Henry Bessemer.

Explanation:

answer; /// the correct answer is evidence of the olmec civilization has been found in southern american in a hot steamy forest, archaeologists have found earthen artifacts at several sites that were evidence of the olmec civilization. these   artifacts were mounds,courtyards and pyramids build of stones, also on top of the mounds were many monuments made of stone, some of these stone structures are very large, they weigh as much as 44

they remained in rural areas and worked at jobs such as lumbering or farming.