
The Top Secret Vault for Ancient Maize
Clip: Episode 4 | 1m 30sVideo has Closed Captions
Shane dives into Mexico's cornucopia with geneticist Sarah Hearne.
Shane follows geneticist Sarah Hearne into a vault of over 28,000 species of maize that has weaved itself into the fabric of Mexico's past, present and future. But in the last century, just a handful of varieties have come to dominate global corn production. What happened?

The Top Secret Vault for Ancient Maize
Clip: Episode 4 | 1m 30sVideo has Closed Captions
Shane follows geneticist Sarah Hearne into a vault of over 28,000 species of maize that has weaved itself into the fabric of Mexico's past, present and future. But in the last century, just a handful of varieties have come to dominate global corn production. What happened?
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Surprising Moments from Human Footprint
Do you think you know what it means to be human? In Human Footprint, Biologist Shane Campbell-Staton asks us all to think again. As he discovers, the story of our impact on the world around us is more complicated — and much more surprising — than you might realize.Providing Support for PBS.org
Learn Moreabout PBS online sponsorshipThis is the most secure vault we have on this site.
Okay.
I'm excited to see what's behind this vault.
Things that money can't buy.
Meet Sarah Hearn.
She's a good baker and an even better geneticist, working at one of the world's largest seed banks.
You have more security in here than I've seen in any biological building I think I've ever been in.
This is like CDC level.
It is like going into a bank vault.
How many different varieties of maize are in this room?
There are around 28 and a half thousand different kinds of maize.
28 and a half thousand.
This is like being in a candy store for me.
They're like jelly beans.
Every different one is a flavor.
There's black corn, blue corn, red, yellow, and white.
Small, medium, and large.
Experimentation by native peoples created tens of thousands of varieties of maize, each one adapted to a specific time, place, and purpose.
But in the last century, just a handful of commercial varieties have come to dominate global corn production.
What happened?
The Cat Tracking Device of the Future
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Dr. Roland Kays uses a global GPS tracker plan to unleash the secret lives of wild cats. (3m 25s)
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Shane meets with local Mexican chefs committed to reviving the sacred heritage of maize. (1m 30s)
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Shane meets five species that made allies of humans. (30s)
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