is the eiffel tower made of steel or iron
Eiffel Tower The Eiffel Tower (/ˈaɪfəl ˈtaʊ.ər/ EYE-fəl TOW-ər; French: tour Eiffel, pronounced [tuʁ‿ɛfɛl]  listen) is a wrought iron lattice tower on the Champ de Mars in Paris, France. It is named after the engineer Gustave Eiffel, whose company designed and built the tower.
Eiffel Tower Work on the foundations started on 28 January 1887.[15] Those for the east and south legs were straightforward, with each leg resting on four 2 m (6.6 ft) concrete slabs, one for each of the principal girders of each leg. The west and north legs, being closer to the river Seine, were more complicated: each slab needed two piles installed by using compressed-air caissons 15 m (49 ft) long and 6 m (20 ft) in diameter driven to a depth of 22 m (72 ft)[16] to support the concrete slabs, which were 6 m (20 ft) thick. Each of these slabs supported a block of limestone with an inclined top to bear a supporting shoe for the ironwork.