The Sky at Night looks back at the last ten years of astronomy and ponders the most significant milestones and revelations. With the help of six distinguished astronomers, Chris and Maggie consider the state of astronomy in 2020 and wonder what new, exciting discoveries await us across the rest of the decade, as a host of new ground and space telescopes come online. Astronomer Royal Lord Martin Rees is among the guests to walk along the Astronomical Wall of Discovery in this one-hour special.

Presenter Michael Wood seeks out the achievements of the country’s golden age, discovering how India discovered zero, calculated the circumference of the Earth and wrote the world’s first sex guide, the Kama Sutra. In the south, he visits the giant temple of Tanjore and sees traditional bronze casters, working as their ancestors did 1,000 years ago.

Through ancient manuscripts and oral tales Michael Wood charts the first human migrations out of Africa. He travels from the tropical backwaters of South India through lost ancient cities in Pakistan to the vibrant landscapes of the Ganges plain. In Turkmenistan dramatic archaeological discoveries cast new light on India’s past.

Professor Jim Al-Khalili investigates one of the most important concepts in the world today - information. He discovers how we harnessed the power of symbols, everything from the first alphabet to the electric telegraph through to the modern digital age. But on this journey he learns that information isn't just about human communication, it's woven very profoundly into the fabric of reality.

This four-part British television series outlines aspects of the history of mathematics. Written and presented by University of Oxford professor Marcus du Sautoy, it is a co-production between the Open University and the BBC. In the first episode, Marcus du Sautoy in Egypt uncovers use of a decimal system based on ten fingers of the hand and discovers that the way we tell the time is based on the Babylonian Base 60 number system. In Greece, he looks at the contributions of some of the giants of mathematics including Plato, Archimedes and Pythagoras, who is credited with beginning the transformation of mathematics from a counting tool into the analytical subject of today. A controversial figure, Pythagoras’ teachings were considered suspect and his followers seen as social outcasts and a little be strange and not in the norm. There is a legend going around that one of his followers, Hippasus, was drowned when he announced his discovery of irrational numbers. As well as his work on the properties of right angled triangles, Pythagoras developed another important theory after observing musical instruments. He discovered that the intervals between harmonious musical notes are always in whole number intervals.

David Attenborough discovers the plants that have evolved to shed their dependency on water enabling them to survive in the driest environments. The story begins at midnight in midsummer as David steps into the Princess of Wales Conservatory to witness the extraordinary nocturnal blooming of a cactus. The queen of the night, with its giant flowers, is the centre piece of a stunning symphony of cacti blooms that burst open in the desert (and at Kew) at night. In a mesmerizing 3D slow motion sequence, we discover the extraordinary connections between cacti and their natural pollinators: bats. As the sun rises, David meets other amazing plants. Species like the century plant, the Agave franzosini, which grows steadily for over 50 years, only to then flower itself to death with one mighty telegraph pole sized bloom which literally bursts out of the roof of Kew’s green house.