From stars, galaxies and moons to subatomic particles, black holes and invisible phenomena, discover the most bizarre, mysterious and exotic things in our universe

Rome was once a largely democratic society, with regular elections. This Republic lasted for 500 years, but then came Tiberius Gracchus. He believed in the ideals of the Republic - fairness, decency and justice for everyone -but was appalled by Rome's aristocrats' treatment of the poor. So he unleashed the power of the mob upon the streets of Rome, with devastating consequences.

At a time when the Earth’s surface is changing faster than ever in human history, watch cities grow, forest disappear and glaciers melt.
In the ever-growing grey of cities one man is feeding thousands of parakeets; in Sumatra a female orang-utan and her daughter face life in a forest under threat; while in Tanzania local people use satellites to replant a forest, securing the future for a family of chimpanzees. This is our home as we’ve never seen it before.

Andrew Graham-Dixon retraces Vasari's footsteps for this captivating two-part film in a short Art of Italy season. He's an enthusiastic guide, lapsing easily into Italian conversation with the custodians of galleries and chapels who allow him a private view. From Brunelleschi's Duomo in Florence to less familiar marvels - a Donatello sculpture; Masaccio frescoes - he illustrates how rapidly ideas developed. A final treat for him - and us - is a tour of the Vasari Corridor, a rarely accessed gallery that zigzags across the Florentine rooftops.

Award winning wildlife photographers Jonathan and Angela Scott have travelled the world, always returning home to Kenya. There they introduced the world to the big cats of the Maasai Mara and now they are part of its fight for survival.

Some of the world's leading physicists believe they have found startling new evidence showing the existence of universes other than our own. One possibility is that the universe is so vast that an exact replica of our solar system, our planet and ourselves exists many times over. These Doppelganger Universes exist within our own Universe; in what scientist now call "The Multiverse." If proof is found it will change our lives, our minds, our planet, our science and our universe.