Particle physicist Prof. Brian Cox asks, 'What time is it?' It's a simple question and it sounds like it has a simple answer. But do we really know what it is that we're asking? Brian visits the ancient Mayan pyramids in Mexico where the Maya built temples to time. He finds out that a day is never 24 hours and meets Earth's very own Director of Time. He journeys to the beginning of time, and goes beyond within the realms of string theory, and explores the very limit of time. He discovers that we not only travel through time at the speed of light, but the experience we feel as the passing of time could be an illusion.

Writing itself is 5,000 years old, and for most of that time words were written by hand using a variety of tools. The Romans were able to run an empire thanks to documents written on papyrus. Scroll books could be made quite cheaply and, as a result, ancient Rome had a thriving written culture. With the fall of the Roman Empire, papyrus became more difficult to obtain. Europeans were forced to turn to a much more expensive surface on which to write: Parchment. Medieval handwritten books could cost as much as a house, they also represent a limitation on literacy and scholarship.
No such limitations were felt in China, where paper had been invented in the second century. Paper was the foundation of Chinese culture and power, and for centuries how to make it was kept secret. When the secret was out, paper mills soon sprang up across central Asia. The result was an intellectual flourishing known as the Islamic Golden Age. Muslim scholars made discoveries in biology, geology, astronomy and mathematics. By contrast, Europe was an intellectual backwater.
That changed with Gutenberg’s development of movable type printing. The letters of the Latin alphabet have very simple block-like shapes, which made it relatively simple to turn them into type pieces. When printers tried to use movable type to print Arabic texts, they found themselves hampered by the cursive nature of Arabic writing. The success of movable type printing in Europe led to a thousand-fold increase in the availability of information, which produced an explosion of ideas that led directly to the European Scientific Revolution and the Industrial Revolution that followed.

The world couldn't keep its eyes off two athletes at the 1994 Winter Games in Lillehammer - Nancy Kerrigan, the elegant brunette and Tonya Harding, the feisty blonde engulfed in scandal. Just weeks before the Olympics on January 6, 1994 at the U.S. Figure Skating Championships, Kerrigan was stunningly clubbed on the right knee by an unknown assailant and left wailing, 'Why, why, why?'
As the bizarre 'why' mystery unraveled, it was revealed that Harding's ex-husband, Jeff Gillooly, had plotted the attack with his misfit friends to literally eliminate Kerrigan from the competition. Now two decades later, The Price of Gold takes a fresh look at the worldwide spectacle that elevated the popularity of professional figure skating and has Harding still facing questions over what she knew when she knew it.

VICE makes history on a trip to North Korea to play hoops and meet with supreme leader Kim Jong-un. With NBA great Dennis Rodman and a trio of Harlem Globetrotters in tow, we traveled to the capital of Pyongyang for a tour of the city, a basketball clinic, an exhibition game, and a first-ever meeting between the leader and an American delegation.

the final episode deals with plants that live in hostile environments. Attenborough visits Ellesmere Island, north of the Arctic Circle, to demonstrate that even in a place that is unconducive to life, it can be found. Algae and lichens grow in or on rock, and during summer, when the ice melts, flowers are much more apparent. However, they must remain close to the ground to stay out of the chilling wind. In the Tasmanian mountains, plants conserve heat by growing into 'cushions' that act as solar panels, with as many as a million individual shoots grouped together as one. Others, such as the lobelia in Mount Kenya, have a 'fur coat' of dense hairs on their leaves. The saguaro cactus in the Sonoran Desert flourishes because of its ability to retain vast amounts of water, which can't be lost through leaves because it has none. Many desert dwellers benefit from an accelerated life cycle, blooming rapidly within weeks after rainfall. Conversely, Mount Roraima is one of the wettest places on Earth. It is a huge sandstone plateau with high waterfalls and nutrients are continuously washed away, so plants have to adapt their diet if they are to survive. A bladderwort is shown invading a bromeliad. Inhabitants of lakes have other problems to contend with: those that dominate the surface will proliferate, and the Amazon water lily provides an apt illustration. Attenborough ends the series with an entreaty for the conservation of plant species.

Carlsbad Caverns are located in the Chihuahuan Desert of southern New Mexico, within the Carlsbad Caverns National Park. There are more than 100 caves. The Natural Entrance is a path into the namesake Carlsbad Cavern. Stalactites cling to the roof of the Big Room, a huge underground chamber in the cavern.