It was the defining moment of the 20th Century - the scientific, technological, military, and political gamble of the world's first atomic attack. This drama-documentary attempts to do what no other film has done before - to show what it is like to live through a nuclear explosion, millisecond by millisecond. Set in the three weeks from the first test explosion in New Mexico to the eventual dropping of the bomb, the action takes viewers into the room where the crucial political decisions are made; on board the Enola Gay on her fateful voyage; inside the bomb as it explodes; and on the streets of Hiroshima when disaster strikes. Parallel storylines interweave, unfolding the action from both US and Japanese perspectives, and revealing the tensions and conflicts in the actions and minds of people who were making history. Special effects recreate the reality of the mission - even going inside the workings of the bomb - and archive film replays the horrific aftermath.

The world's deserts are lands of extremes that force animals to come up with ingenious ways of coping with hostile conditions, giving rise to the most incredible survival stories on earth. A pride of desert lions are so hungry they risk hunting a giraffe several times their size, while male sandgrouse fly 120 miles each day to the nearest waterhole and dice with death to collect water for their chicks. Filmed for the first time, a tiny bat does battle with one of the world's deadliest scorpions, and in Madagascar, a locust swarm of biblical proportions is seen as never before.

The third episode is devoted to the ways in which plants reproduce. Pollen and a stigma are the two components needed for fertilisation. Most plants carry both these within their flowers and rely on animals to transport the pollen from one to the stigma of another. To do this, they attract their couriers with colour, scent and nectar. It isn't just birds that help pollination: some mammals and reptiles also do so. However, it is mostly insects that are recruited to carry out the task. To ensure that pollen is not wasted by being delivered to the wrong flower, some species of plant have developed exclusive relationships with their visitors, and the gentian and its attendant carpenter bees is one example. Since pollen can be expensive to produce in terms of calories, some plants, such as orchids, ration it by means of pollinia and a strategically placed landing platform. Other orchids offer no reward for pollination, but instead mislead their guests by mimicking their markings and aroma, thus enticing males to 'mate' with them (Pseudocopulation). The most extreme fertilisation method is one of imprisonment, and one plant that uses it is the dead horse arum. It is often found near gull colonies, and mimics the appearance and smell of rotting flesh. Blow-flies are attracted to it, and are forced to stay the night before being allowed to depart in the morning, laden with pollen. Finally, Attenborough introduces the world's largest inflorescence: that of the titan arum.

Although the end of the Soviet Union also meant the end of the KGB, it did not mean the end of secret service activities. FSB and the foreign intelligence service SVR took over the tasks. Under the secret service officer Vladimir Putin, the tasks of the secret service were redefined, and digital age with the Internet brought new possibilities for internal and external espionage and for the manipulation of public opinion.
Coup d'etats, assassinations, sex scandals, radioactive poisoning....it's the stuff of a Bond movie. But in today's Russia, it's all very real. Under Vladimir Putin, the FSB rules Russia with an iron rod directly from the Kremlin. To challenge its authority, even from apparent safety abroad, means risking your life. The KGB has even managed to outlive communism itself. Today, Russia is no longer a State with a Security Service: instead, the Security Service has a State.

Widespread dietary changes are needed if we’re to combat the range of health problems associated with obesity and the environmental damage caused by industrial farming. Switching to a vegan diet is a potential solution, but selling the idea to the meat-eaters around the world is a tricky proposition.

The fifth episode explores how the deportation of Hungary's Jews in 1944 precipitated the most intensive slaughter in Auschwitz's history.