The drug policies have remained unchanged over the last 40 years so should they be reformed in the light of new research? Recent research has analysed the link between the harmful effects of drugs relative to their current classification by law with some startling conclusions. Perhaps most startling of all is that alcohol, solvents and tobacco (all unclassified drugs) are rated more dangerous than ecstasy, 4-MTA and LSD (all class A drugs).

Attenborough's journey continues in Canada's Rocky Mountains, where fossils document an explosion in animal diversity never seen before or since. Travelling from there to North Africa, the rainforests of Australia and the east coast of Scotland, Attenborough discovers how animals evolved to conquer not only the oceans but also the land and air. These remote and fascinating creatures are brought to life as never before with the help of cutting-edge scientific technology and photorealistic visual effects. From the first large predators to the first legs on land, these were creatures that evolved the traits and tools that allow all animals, including ourselves, to survive to this day.

Hernan Cortes left Cuba in 1519 seeking riches in the island to the west. Instead he discovered, and ultimately destroyed, a hitherto unknown civilization. Join Micheal Wood as he retraces this fateful expedition. Read Spanish eyewitness accounts that describe the conquistadors' awe at the Aztec achievements and the lust for native treasure. Learn the Aztec' side of the story by scrolling trough pictographs that tell of the agonizing fall of the empire.

Just 92 elements made up the world, but the belief that were only four - earth, fire, air and water - persisted until the 19th Century. Professor Al-Khalili retraces the footsteps of the alchemists who first began to question the notion of the elements in their search for the secret of everlasting life.He reveals the red herrings and rivalries which dogged scientific progress, and explores how new approaches to splitting matter brought us both remarkable elements and the new science of chemistry.

This programme focuses on the most famous Roman of all - Caesar. Charming, savage, power-crazed, opportunistic and brilliant, he overthrew a 500-year-old Republic and began the age of the emperors.

In this documentary we will be transported into the world of ants. What animal has achieved immortality? What animal is the most warlike? What animal has the greatest supercity on the planet? Not man but ants. They are the real success story. It is only their tiny size and our vanity that allows us to hold onto the myth of our supremacy. Ants rule the planet. They are found in more habitats from far northern Finland to the sweltering tropics. The largest colony known of these insects is in Japan, where 306 million ants, with 1 million queens, in 45,000 colonies spread over 270 hectares. The fiercest warriors on earth are the slave maker ants. Other ants have barracks and sentry posts to protect themselves against surprise attack.