Cement and Concrete

Cement is a rock like substance that holds things together, the ancient romans invented cement it was very important to roman society because it let them build aqueducts. Cement is made when lime stone is heated to 1400°C. 
Concrete is made with cement with sand gravel and stone and is much stronger than cement.
Concrete is used for sidewalks, foundations, tunnels, bridges and roads.
Hear are some photos of concrete.