The biggest rabbit-hole in history: the search of the smallest thing in the Universe. It is a journey where things don't just become smaller but also a whole lot weirder. Scientists hope to catch a glimpse of miniature black holes, multiple dimensions and even parallel Universes. As they start to explore this wonderland, where nothing is quite what it seems, they may have to rewrite the fundamental laws of time and space.

Here, Aleks charts how the Web is forging a new brand of politics, both in democracies and authoritarian regimes. With contributions from Al Gore, Martha Lane Fox, Stephen Fry and Bill Gates, Aleks explores how interactive, unmediated sites like Twitter and YouTube have encouraged direct action and politicised young people in unprecedented numbers. Yet, at the same time, the Web's openness enables hardline states to spy and censor, and extremists to threaten with networks of hate and crippling cyber attacks.

Dr Adam Rutherford shows how decoding the genome has led us to begin to understand the very process by which our DNA makes us different; how it makes each one of us on earth unique and influences who we are and the traits we have. He reveals how, as we try and understand the relationship between who we are and our genes, we stand at the beginning of the most exciting scientific journey of all time.

One of the Universe's most enduring mysteries is Time Travel. In this episode, we explore the possibilities. Discover why Time Travel into the future is unavoidable in the Einsteinian world of Relativity. As for the past... the laws of physics do not tell us it's impossible, but the bizarre consequences of going into the past and altering the future make for mind-bending science. Finally, we go for the future by traveling to the nearest star, 4.3 light years away... in only 45 days. Our destination may be an Earth-like planet; a planet scientists are now hunting for, and may find in the next 3 to 4 years.

Zachary Quinto charts a journey to determine whether time travel is possible. He meets a man who claims to have traveled back in time due to a secret government program and a group of people living in Liverpool known as 'time slippers'.
Zachary makes a visit to the CERN headquarters in Geneva, where he attempts to understand the origins of the universe and the dimension of time. Equipped with this new knowledge, Zachary tests his own perception of time with an elaborate skydiving experiment to see if he can slow down time itself.

What sort of alien civilizations might exist in the vastness of space? Terra is the fictional world imagined in Episode 4, a planet nine billion years old, twice as old as Earth. Old enough that a truly advanced intelligence could evolve. It was once a fertile world, now it is barren. But life can still thrive here in artificial domes. Over time, they've evolved not to need their bodies. They exist only as neural tissue. They never age, they never die. They're monitored and maintained by robots.
If alien civilizations are statistically so likely, why haven't astronomers found any sign of them? Where is everyone? Every time we look at an individual star, that's like dropping a bucket in the ocean. We're going to have to look at a lot of stars and to search through a lot of data until we find the clue that leads us to another civilization.