NOVA Season 21 Episode release dates & where to watch

1. Codebreakers

NOVA delves into the history of secret communications and the people who wrack their brains to decipher them. The program probes the most celebrated of all cryptographic coups: the breaking of the World War II codes used by Japan and Germany and how codebreaking helped shorten the war.

2. Dinosaurs of the Gobi

Velociraptors and primitive birds are among the fabulous fossil finds as NOVA accompanies an American Museum of Natural History expedition to the Gobi Desert. The trip relives the exploits of the Museum's dashing explorer of the 1920s, Roy Chapman Andrews -said to be the real-life model for Indiana Jones.

3. Daredevils of the Sky

NOVA follows members of the US Aerobatic Team as they prepare for and compete in the 1992 World Aerobatic Championship. The sport, as precisely choreographed as gymnastics-except that it takes place in airplanes at 200 miles per hour-has always been on the leading edge of developments in aviation.

4. Journey to Kilimanjaro

NOVA explores ice-capped mountains-on the equator. These African giants are magical islands of life towering above the scorched plains. Giant forest hogs, bearded vultures, the elusive bongo and other exotic creatures live in this harsh and isolated high country.

5. Can Chimps Talk?

NOVA covers exciting and controversial research with chimpanzees who have been trained to express themselves with human symbols. Are they speaking their minds? Or are they just aping their trainers?

6. In Search of Human Origins, Part One

In the first of a three-part series, noted anthropologist Donald Johanson probes the earliest ancestors of the human species - reaching back more than three million years to a strange ape who walked upright. Johanson takes viewers to the site in Ethiopia where he discovered the fossil remains of this missing link nicknamed "Lucy."

7. In Search of Human Origins, Part Two

Anthropologist Donald Johanson looks at how our human ancestors of two million years ago made their living. Contrary to popular myth, scavenging was a more lucrative living than hunting-and may have contributed to the development of human intelligence.

8. In Search of Human Origins, Part Three

At what point did our distant ancestors become anatomically like us? And, more importantly, when did they begin to act like us? Anthropologist Donald Johanson looks at what it is that makes us human.

9. Can China Kick the Habit?

NOVA visits the most cigarette-addicted nation in the world-China. Western advertising and trading practices have exacerbated the fatal romance with smoking in the world's most populous country, where lung cancer cases are beginning to strain the nation's health care system.

10. Aircraft Carrier!

NOVA experiences the relentless, round-the-clock life aboard the US Navy aircraft carrier, Independence-where every day is a constant drill of launching and landing aircraft atop a floating city of 5,000 people. The action includes Top Gun mock combat exercises and live-ammunition patrols over Iraq.

11. The Great Wildlife Heist

Polly wants a crackdown when it comes to the illegal trade in the world's most beautiful and intelligent birds: parrots. NOVA goes undercover with a US government sting that breaks an international parrot smuggling ring, landing some surprising suspects.

12. Secret of the Wild Child

NOVA profiles "Genie," a girl whose parents kept her imprisoned in near total isolation from infancy. When social workers discoverd her as a teenager, Genie had not learned to walk or talk. This NOVA documentary includes never-before-seen footage of Genie during her rehabilitation and probes how and when we learn the skills that make us "human."

13. Haunted Cry of a Long Gone Bird

NOVA explores the legacy of the great Auk, a magnificent flightless bird that was hunted to extinction over a century ago. In a journey retracing its migratory route, host Richard Wheeler kayaks from Newfoundland to Cape Cod and discovers that other marine species face the Auk's luckless fate.

14. What's New About Menopause

NOVA tackles the long-taboo subject of menopause, profiling new research and examining the medical and ethical controversies that arise when science enables women to postpone menopause or even to bear children long after "the change." Stockard Channing narrates.

15. The Tribe that Time Forgot

NOVA travels deep into the Amazon wilderness in search of a mysterious tribe- a tribe that dismembered and partially ate three prospectors in 1976. Locating the group, NOVA lives with them for three months, gaining insight into the customes and beliefs of a people whose lifestyle has not changed for centuries.

16. Killer Quake!

NOVA probes the 1994 Los Angeles earthquake. Even as the city struggles to repair itself from the tragedy, seismic pressure continues to build. Scientists fear that newly discovered faults could, at any moment, trigger California's most devastating natural disaster.

17. Buried in Ash

Ten million years ago, an enormous volcanic eruption buried much of what is now Nebraska in up to 10 feet of ash, preserving countless skeletons of prehistoric big game animals. NOVA joins the discoverer of this treasure trove to learn what life was like when a lot more than buffalo roamed the West.

18. Rescue Mission in Space

Hobbled by defective eyesight because of its original, bungled prescription, the Hubble Space Telescope was recently repaired in a dramatic Space Shuttle mission. NOVA follows the exploits of astronauts who saved the day, and the stunning work that Hubble has performed in the months since its repair.

19. Journey to the Sacred Sea

NOVA travels to Lake Baikal, the world's oldest and deepest lake, containing one-fifth of all the fresh water on Earth. Investigating Baikal from above, below and all around, NOVA charts its dramatically changing environment over the course of four seasons.

20. In Search of the First Language Finale

NOVA explores the common threads that link the more than 5,000 languages of Earth, including a controversial theory that claims to reconstruct words from a time when only a handful of languages were spoken, recalling the biblical story of the Tower of Babel.