Calcium

Nottingham sits upon a soft sandstone ridge which means water courses running through rocks and simple tools helped to create cave dwellings. Underneath the City streets is a hidden maze of 500 original caves dating back to the dark ages.

Uses of the caves include; the only medieval underground tannery in the country, an Anderson air raid shelter where thousands of people sought refuge during World War II and the remnants of Victorian slums.

The name is derived from the Latin 'calx' meaning lime.

Calcium is a silvery-white, soft metal that tarnishes rapidly in air and reacts with water.

Calcium is essential to all living things, particularly for the growth of healthy teeth and bones.