I'm Nicola Cochlin and for BBC Radio 4, this is history's youngest heroes. Rebellion, risk and the radical power of youth.

She thought, right, I'll just do it. She thought about others rather than herself.

Twelve stories of extraordinary young people from across history.

There's a real sense of urgency in them. That resistance has to be mounted. It has to be mounted now. across history. There's a real sense of urgency in them.

That resistance has to be mounted.

It has to be mounted now.

Follow History's youngest heroes, wherever you get your podcasts.

In Mississippi, Yazoo Clay keeps secrets.

Seven thousand bodies out there or more. A forgotten asylum cemetery. It was my family's

mystery. Shame, guilt, propriety, something keeps it all buried deep until it's not. I'm Larison

Campbell and this is under Yazoo Clay. Listen on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast.

Hello, my name is Adrian Bain, and I'm a producer at Wonder Media Network.

And I'm so excited to be guest hosting this episode

of Wamanica.

This month, we're talking about cultivators, women who nurtured, cross-pollinated, experimented,

or went to great lengths to better understand and protect the natural world.

Today, we're talking about a pioneering cactus researcher who became Mexico's first certified biologist.

She co-founded the Mexican Society of Cactology and classified over 700 cacti species, many of which her efforts helped preserve.

Please welcome Elia Bravo Olis.

Elia Bravo Olis was born on September 30th, 1901 in Mishkoak, a neighborhood on the edge of Mexico City. To the west were low hills shaded by oaks and pines, and to the east open plains where cows roamed freely.

The sky was so clear. In the mornings, Elia could see the planet Venus. Growing up, immersed in nature,

Elia spent her days swimming in the neighborhood river

...