In the 80s the nature of the Latino Diaspora changes again. From Cuba a second wave of refugees to United States – the Mariel exodus – floods Miami . The same decade sees the sudden arrival of hundreds of thousands of Central Americans (Salvadorans, Guatemalans, and Nicaraguans) fleeing death squads and mass murders at home like activist, Carlos Vaquerano. By the early 1990s, a political debate over illegal immigration – has begun. Globalization, empowered by NAFTA, means that as U.S. manufacturers move south, Mexican workers head north in record numbers. A backlash ensues: tightened borders, anti-bilingualism, state laws to declare all illegal immigrants felons. But a sea change is underway: the coalescence of a new phenomenon called Latino American culture-as Latinos spread geographically and make their mark in music, sports, politics, business, and education.

This is the story of three maps, three 'visions' of London over three centuries. The Morgan Map of 1682 was the first to show the whole of the City of London after the Great Fire of London. In 1746 John Rocque produced at the time the most detailed map ever made of London. Like Morgan's, Rocque's map is all neo-Classical beauty and clinical precision, but the London it represented had become the opposite. In engravings of the time, such as Night, the artist William Hogarth shows a city boiling with vice and corruption. Stephen Walter's contemporary image, The Island, plays with notions of cartographic order and respectability. His extraordinary London map looks at first glance to be just as precise and ordered as his hero Rocque's but, looking closer, it includes 21st century markings such as 'favourite kebab vans' and sites of 'personal heartbreak'.

The series concludes by delving into the world of satirical maps. How did maps take on a new form, not as geographical tools, but as devices for humour, satire or storytelling? Graphic Artist Fred Rose perfectly captured the public mood in 1880 with his General Election maps featuring Gladstone and Disraeli, using the maps to comment upon crucial election issues still familiar to us today. Technology was on the satirist's side with the advent of high-speed printing allowing for larger runs at lower cost. In 1877, when Rose produced his 'Serio Comic Map of Europe at War', maps began to take on a new direction and form, reflecting a changing world. Rose's map exploited these possibilities to the full using a combination of creatures and human figures to represent each European nation. The personification of Russia as a grotesque-looking octopus, extending its tentacles around the surrounding nations, perfectly symbolised the threat the country posed to its neighbours.

This episode covers the nature of how life may have developed on Earth and the possibility of life on other planets. Tyson begins by explaining how the human development of writing systems enabled the transfer of information through generations, describing how Princess Enheduanna ca. 2280 BCE would be one of the first to sign her name to her works, and how Gilgamesh collected stories, including that of Utnapishtim documenting a great flood comparable to the story of Noah's Ark. Tyson explains how DNA similarly records information to propagate life, and postulates theories of how DNA originated on Earth, including evolution from a shallow tide pool, or from the ejecta of meteor collisions from other planets. In the latter case, Tyson explains how comparing the composition of the Nakhla meteorite in 1911 to results collected by the Viking program demonstrated that material from Mars could transit to Earth, and the ability of some microbes to survive the harsh conditions of space. With the motions of solar systems through the galaxy over billions of years, life could conceivably propagate from planet to planet in the same manner. Tyson then moves on to consider if life on other planets could exist. He explains how Project Diana performed in the 1960s showed that radio waves are able to travel in space, and that all of humanity's broadcast signals continue to radiate into space from our planet. Tyson notes that projects have since looked for similar signals potentially emanating from other solar systems. Tyson then explains that the development and lifespan of extraterrestrial civilizations must be considered for such detection to be realized. He notes that civilizations can be wiped out by cosmic events like supernovae, natural disasters such as the Toba disaster, or even self-destruct through war or other means, making probability estimates difficult. Tyson describes how elliptical galaxies, in which some of the oldest red dwarf stars exist, would offer the best chance of finding established civilizations. Tyson concludes that human intelligence properly applied should allow our species to avoid such disasters and enable us to migrate beyond the Earth before the Sun's eventual transformation into a red giant.

During a Gurkha recruitment Palin is disturbed by Maoist insurgents, but survives to suffer as he climbs to 15,000 feet and sees the majesty of Annapurna Sanctuary. In Kathmandu he is blessed by the Nepalese king before meeting some holy men. Crossing into Tibet, he meets his first yaks at the highest monastery in the world, before heading up the Rongbuk glacier towards the summit of Everest.

Leaving Everest base camp to take the high road to Lhasa to see what the Chinese have done to Tibet. He sees that religion is once again tolerated, while the old Tibetan centre of the city is being replaced with modern Chinese shopping malls and nightclubs. Following the pilgrims to the holy Namtso Lake, he gets warm in a hot spring before learning how to milk a yak with a nomad family.