SoHo boasts the greatest collection of cast-iron architecture in the world. Approximately 250 cast-iron buildings stand in New York City, and the majority are in SoHo. Cast iron was initially used as a decorative front over a pre-existing building. With the addition of modern, decorative facades, older industrial buildings were able to attract new commercial clients. Most of these facades were constructed during the period from 1840 to 1880. In addition to revitalizing older structures, buildings in SoHo were later designed to feature the cast iron.