Back to Show
NOVA
These Ancient Stones Helped Track the Seasons
Along the river Gambia in Senegal, there are more than a thousand stone circles. The people who placed these stones would have observed how the locations of sunrise and sunset varied over the year.
Support Provided By

53:30
Explore the promise and perils of new A.I. technologies.

53:10
Follow the quest to recover DNA millions of years old for the very first time.

53:29
Explore the engineering behind Paris’s iconic landmark, the tallest structure of its time.

53:17
New evidence reveals the real story of Easter Island and the builders of its stone heads.

53:31
Giant fossils uncovered in the Sahara Desert reveal new secrets of how whales evolved.

Unlock with PBS Passport
53:30
A family turns to science in their struggle to rediscover a history obscured by slavery.

53:54
Follow the quest to create a lifesaving malaria vaccine.

53:20
The inside story of China’s meteoric rise to the forefront of global innovation.

Unlock with PBS Passport
53:15
How did Earth give rise to humans? See what made our species' existence possible.

Unlock with PBS Passport
53:45
How did life bounce back after a cataclysmic extinction wiped out some 90% of all species?

Unlock with PBS Passport
53:47
See how life made the leap to land, turning a barren landscape into a lush, green world.

Unlock with PBS Passport
53:46
How did life survive on a planet covered in ice from pole to pole?