Most people never give concrete a second thought. This is a mistake. Concrete is one of the most versatile and widely used building materials known, and it has been known for a long time. Concrete like materials have been unearthed in ancient Egypt, and the Romans made extensive use of it. Concrete structures over 2000 years old are still in use today.
Roman concrete is very different than modern concrete, and it did not weather well. Thus, Roman structures were often faced with stone or brick to increase durability. This defect has been overcome with modern materials and production techniques.