Spain is found at the crossroads between the Mediterranean and the Atlantic, between Europe and Africa, resulting in diverse landscapes, ancient cultures and magnificent wildlife. It's a hidden Spain missed by many tourists who fail to venture outside the resorts. Worlds within worlds, the medieval towns, to farming communities, desert, mountains and forests with some of the most dramatic and diverse wildlife of the continent.

Explore the hottest area of bioscience, genomics with stunning live image, quality CGI, the forefront research, and real human stories.
Previously it was thought that only 2% of our DNA is meaningful and the remaining 98% is non-coding 'junk'. But today we are beginning to know how the junk part of our DNA works to decide our personal characteristics and tendencies.

In the days of the Mayas, cenotes – deep, natural pits on the Yucatan peninsula - provided the only means of obtaining drinking water. But in the mythology of this advanced civilisation, these waterholes and caves were also the entrance to Xibalba – the underworld. All deceased were obliged to pass through Xibalba and wait there until they were called into heaven. It was a place in which one made sacrifices to the gods – objects of daily life, as well as bloody, human sacrifices. To this day, the relics of these acts are still in place preserved underwater for more than a thousand years. The entrance to the underworld begins at a dirty waterhole in the middle of the Mexican jungle overgrown and barely recognisable. But immediately after entry, a hall of breath-taking dimensions and beauty is revealed. As if they were sculptures, stalactites and stalagmites lend the underwater cave an almost sacred ambience. By now, one has succumbed to the fascination emanated by the world’s largest underwater cave system. We accompany four professional research divers to Yucatan – a team of specialists, able to squeeze their bodies through crevices and holes, barely larger than their bodies and who master dives that would push even the most experienced divers to their limits. With them, we penetrate worlds only a few people have ever ventured into. We encounter the remains of human victims, prehistoric fireplaces and primeval animal skeletons and undertake a dive, which takes us from the primeval forest to the open sea. We then enter Xibalba – the place of myths and the dead. In the days of the Mayas - a voyage of no return. Today, this is one of the greatest challenges one can face as a diver – the hidden world of the underwater caves of Yucatan – all filmed in 3D.

This episode explores the wave theory of light as studied by mankind, noting that light has played an important role in scientific progress, with such early experiments from over 2000 years ago involving the camera obscura by the Chinese philosopher Mozi. Tyson describes the work of the 11th century Arabic scientist Ibn al-Haytham, considered to be one of the first to postulate on the nature of light and optics leading to the concept of the telescope, as well as one of the first researchers to use the scientific method. Tyson proceeds to discuss the nature of light as discovered by mankind. Work by Isaac Newton using diffraction through prisms demonstrated that light was composed of the visible spectrum, while findings of William Herschel in the 19th century showed that light also consisted of infrared rays. Joseph von Fraunhofer would later come to discover that by magnifying the spectrum of visible light, gaps in the spectrum would be observed. These Fraunhofer lines would later be determined to be caused by the absorption of light by electrons in moving between atomic orbitals when it passed through atoms, with each atom having a characteristic signature due to the quantum nature of these orbitals. This since has led to the core of astronomical spectroscopy, allowing astronomers to make observations about the composition of stars, planets, and other stellar features through the spectral lines, as well as observing the motion and expansion of the universe, and the existence of dark matter.

This featured film sheds new light on a possible cover up spanning two continents. It's not only a tale about the airship's demise, but sinister secrets including ties to the Nazi party. Plus rarely seen footage of crash from inside the ship.

The 1980s was an era in which a fusillade of new genres emerged, and many are still with us today, such as hip-hop and house. Dylan Jones has mined the archives to select some of the most crucial tracks in the rise of these two genres.
From a young Kurtis Blow making his Top of the Pops debut to the sonic bombardment of Public Enemy and the sampling skills of Bomb the Bass, this episode showcases the evolution in rap and house music across the decade. There are rare archival interviews and stellar performances from Run-DMC, Salt 'N' Pepa, S'Express, Cookie Crew and Neneh Cherry, as well as iconic videos from Herbie Hancock, The Beastie Boys, M/A/R/R/S, Grandmaster Flash and the Furious Five, and many more.