Steel is a very ancient material and a very modern material. It is produced when soft and rust-prone iron is alloyed with carbon. The Iron Age might have been known as the Steel Age as most advances of the Iron Age relate to improvements in the qualities of steel.

Steel came of age as an architectural resource and a designers preferred material in the early 20th century.

The steel based designs for Henri Sullivan's (American architect, 1856 - 1924) skyscrapers reflected his influential dictum "form follows function". The principle that outward form should faithfully express the function beneath was expressed in his writings and works and have greatly influenced the evolution of modern architecture.

In 1927 the design and patent of Mies van der Rohe's (German architect, 1886-1969, right) tubular steel cantilevered chair known as the MR20 brought him into the international spotlight. The character of this chair, and that of many of Mies' other designs, was that of formal, refined comfort.

Inescapably, steel requires high amounts of energy for its production. The greatest attack on Western Europe's ecology was near total deforestation in order to provide the smelters' charcoal.