Manufacturing cast iron became simpler during the Industrial Revolution due to an increase in factories and furnaces. As a result, cast iron became a fairly inexpensive building material. Bridge designers spotted an opportunity in its utilization and began constructing hundreds of new bridges with it. The best quality bridges were made of huge sections of cast iron because no other material could withstand the stress required by their designs. Cast iron's advantages proved to be indispensable for modern infrastructure. Today, cast iron is still used for major components of machinery and industry because it is resistant to corrosion and very efficient at conducting heat. The use of cast iron went out of fashion after the mid-20th century but it has recently been brought back into style as architects and industrial designers seek ways to make using natural materials appealing again. Cast iron is now used instead of steel for some applications because it looks like stone when painted white or black, it feels good under your feet when walking on it, and it doesn't get damaged as easily when hit with a hammer. In conclusion, cast iron is useful because it's strong, durable, and attractive. Its only disadvantage is that it can be difficult to work with because it's hard to cut and shape.