The architectural possibilities for stainless steel were recognized within only a few years of its discovery early in the 20th century. Highly-visible proof can be found in such well-known structures as the roof of the Chrysler Building in New York and the canopy of the Savoy Hotel in London. Increasingly, stainless steel is part of the unseen but vital fabric of a building or structure. Notable examples are fittings for interior plumbing, fixing components for the attachment of stone facades and the use of stainless steel reinforcing bars for concrete structures, for which a long design-life is specified.