Which material was used to build the Eiffel Tower?

The Eiffel Tower was built from wrought iron, specifically puddled iron assembled into a vast lattice structure.

The tower was designed by engineers Maurice Koechlin and Émile Nouguier, with architect Stephen Sauvestre, for the 1889 Exposition Universelle in Paris. Gustave Eiffel's company prefabricated thousands of iron components and joined them with about 2.5 million rivets. The metal was produced at the Forges et Usines de Pompey in eastern France.

The tower contains roughly 7,300 tonnes of structural iron, though its total weight is about 10,100 tonnes after adding lifts, facilities, and antennas. A common mix-up is calling the material steel: steel was already known in the nineteenth century, but the Eiffel Tower's main structure is wrought iron, an iron with very low carbon content that could be forged and shaped. Its open lattice also reduces wind resistance, helping the 300-metre tower remain stable.