13 episodes 94%4KCC

When one decision shifts empires, science, war, and culture.

Explore a season built on the small choices that redirected world history. Across stories of Alexander, medieval kingdoms, Darwin, the atomic bomb, and rock music, each episode traces how a single moment can reshape entire societies. Sign up to see history from the turning points that still echo today.

Episode guide

13 episodes

1Alexander The Great

What if Alexander had not died at the age of 32? What if he had listened to advisors and returned to Macedonia instead of going on his worldwide conquest? How does the legacy of ideals and leadership left from Alexander's time resonate today?

25 min

2Race To The Moon

What is the future of the human presence in space? How might things be different if there had not been a Cold War and a Space Race? What does humanity gain by venturing into our solar system...and beyond?

25 min

3Martin Luther King, Jr.

What would the Civil Rights movement in the USA have been like if Martin Luther King, Jr. had not been motivating change? How does the legacy of the American Civil War still affect the American democracy?

25 min

4King Philippe of France and Richard The Lionheart of England

A series of battles in France had an impact on modern day Europe and the fates of three countries down to our modern century. What might have happened if Richard the Lionheart had not been wounded? Or Philippe Auguste of France had fled the battlefield?

25 min

5Confucius and China

The choices that Kong Qui, known in the West as Confucius, made during his career as a civil servant and administrator influenced an entire civilization. What if Kong Qui had been as opportunistic and corrupt as other officials? How might the fate of China and its worldview be changed?

25 min

6Ghengis Khan

How did the events of his childhood shape the man who would become Genghis Khan? What impact did the Mongol invasions have on the history of Asia and on the psyche of Europe?

25 min

7Charles Darwin

Picture the last two hundred years without the publication of Darwin's "On The Origin of Species" -- how might the scientific conversation have developed? What were the influences in Victorian England during Darwin's youth, and how tenuous was his opportunity for sailing on the Beagle's voyage?

25 min

8Chernobyl

The decisions of only a handful of individuals determined the course of the nuclear disaster at Chernobyl. What transpired over a few hours would have an impact on the local community, Russia, Europe and the globe.

25 min

9Samurai

The shape of Japan's internal politics and the country's response to external influences for centuries can be traced back to the choices of two warlords and a decisive battle. What was the Edo Period and how did it mold Japanese society?

25 min

10Einstein And The Manhattan Project

A famous scientist wrote the President of the United States, and the face of war, and our world, was changed forever. How and why did humanity develop a weapon capable of almost total destruction?

25 min

11Rome vs. Barbarians

The untimely death of the Roman Emperor of the Western Empire and the poor decisions of the Roman Emperor of the Eastern Empire change the fortunes of the Roman Army in their battle with the Goths. And this changes the future of Europe.

25 min

12The Internet

What if the source codes for the internet had remained with the US military, rather than being released to the world? How did our lives of unfettered internet access become a reality?

25 min

13The Birth Of Rock

Elvis Presley paid $4 to record two songs for his mother and the rest, as they say, is history. But without Elvis, would rock and roll have gone the same route? And how have the many iterations of rock and roll developed and changed our taste and culture since the 1950's?

25 min

Good to know

Frequently asked questions

Thousands of the world's best documentaries and factual programming — nature, history, science, technology, and biography — including exclusive Curiosity Originals like Butterfly Effect (Season 1). Stream it all ad-free, anytime.

Plans are billed annually — every plan streams in 4K. The Smart Bundle adds four partner services. There are no contracts — cancel anytime.

Watch on the web, iOS and Android, Roku, Apple TV, Amazon Fire TV, Chromecast, Android TV, and most smart TVs. Start on one device and pick up right where you left off on another.

Yes. The library is full of family-friendly nature and science programming, and the Smart Bundle includes Kidstream — carefully chosen, ad-free shows kids will love and parents can trust.

Absolutely. There are no contracts and no cancellation fees — manage or cancel your plan anytime from your account settings.

Curiosity Stream is our streaming service — thousands of documentaries and originals. The Smart Bundle is Curiosity Stream plus four other independent streaming services (Tastemade, Kidstream, Curiosity University, and SOMM TV) on a single subscription.

Yes. Start on any plan and move up to the Smart Bundle whenever you like — the change takes effect right away, and your billing is simply prorated from your account settings.

Got your answer? Pick a plan and start streaming.Start streaming

Available now

Start watching Butterfly Effect (Season 1) today

Stream thousands of award-winning documentaries. Cancel anytime.

Start streaming