In the final programme in the series we look at the rarest members of the periodic table.
Why do we value this useless metal? And does it bring out the worst in human nature?
This metal offers thousands of years of nuclear energy, but is it any safer than uranium?
Six rare metals that clean the air but are the focus of violent conflict in South Africa.
The poison in everything from paint and sweets, to telegraph polls and drinking water.
The shiniest and showiest of metals has some surprisingly modern applications.
Why does iodine deficiency still blight children in developing countries like India?
Could we finally be about to crack this source of potentially unlimited clean energy?
This toxic metal is being phased out of our lives, but still keeps planes up in the air.
India is completely dependent on imports of potash, a fertiliser essential for crops.