There is one miniature fierce queen, hardly bigger than a grain of rice. Enter the fascinating, and sometimes brutal world of honey ants, struggling not just for survival, but power - all in service of their fearless leader, the queen. Her story has it all-- ambition, murder, and a great army of female warriors on the rampage.

Plants that have developed to thrive in the desert, including cacti that grow in the shade of other trees and collect water in pleated trunks that expand and contract - but can also find themselves a host to other plants, like desert mistletoe. This programme also reveals how tobacco plants being eaten by caterpillars are able to summon the creatures' natural predators, and how tumbleweeds roll across the landscape, only unfurling and growing when they encounter rain.

Around 30% of the land's surface is desert, the most varied of our ecosystems despite the lack of rain. Unravel the secrets of desert survival and experience the ephemeral nature of this dynamic environment. Watch Saharan sandstorms nearly a mile high and desert rivers that run for a single day. In the Gobi Desert, rare Bactrian camels get moisture from the snow. In the Atacama, guanacos survive by licking dew off cactus spines. In the USA, the brief blooming of Death Valley triggers a plague of locusts 65km wide and 160km long. A unique aerial voyage over the Namibian desert reveals elephants on a long trek for food and desert lions searching for wandering oryx.

Our relationship with destruction is not a simple one. It can release endorphins and relax our minds. It can amp us up and make us even more aggressive. It can even help us regulate our emotional reactions. Can violently breaking things calm us down? Or does it simply anger us more? Find out as Michael Stevens takes a look into our urge to destroy.

Follow three women at risk of developing Alzheimer’s and join a groundbreaking study to try to prevent the disease, while sharing their ups and downs, anxiously watching for symptoms, and hoping they can make a difference. Barb, Sigrid, and Karen all had mothers with Alzheimer’s and witnessed first hand the devastation wrought by the disease, not only on the mind and body, but on patients’ families.

We are the only species on earth that cooks its food - and we are also the cleverest species on the planet. The question is: do we cook because we're clever and imaginative, or are we clever and imaginative because our ancestors discovered cooking? Horizon examines the evidence that our ancestors' changing diet and their mastery of fire prompted anatomical and neurological changes that resulted in taking us out of the trees and into the kitchen.