From December 20-31, we’ll be showcasing some of our most popular Think conversations of 2021. We leaned heavily on our podcast audience for suggestions as these show were among the most downloaded episodes of the year. If you missed ’em the first time, this is a great way to catch up!

Why your brain loves a mystery (12/20, 1 p.m. CT)

Jonah Lehrer joined us in August to discuss the psychology, neuroscience, and anthropology of why we love solving puzzles, finding patterns and discovering the unknown. He’s the author of “Mystery: A Seduction, A Strategy, A Solution.”

Where do Asian-Americans “fit”? (12/21, 1 p.m. CT)

Jay Caspian Kang joined us in November to talk about the evolution of what it means to be Asian-American – and about his own family’s story as they found their footings. His book is called “The Loneliest Americans.”

The evolution Of heaven (12/22, 1 p.m. CT)

Catherine Wolff joined us in August to discuss the concept of heaven, how it’s been framed in art, literature and religion through the ages, and how that has changed with modern beliefs. Wolff is the author of “Beyond: How Humankind Thinks About Heaven.”

A look at four lost cities … and why they disappeared (12/23, 1 p.m. CT)

Annalee Newitz, contributing opinion writer for The New York Times, joined us in June to talk about cities that lasted millennia and then disappeared, and the answers they can provide for how we live together today. Newitz is the author of “Four Lost Cities: A Secret History of the Urban Age.”

Was an interstellar object really an alien spacecraft? (12/24, 1 p.m. CT)

Matthew Bothwell is an astronomer at the Institute of Astronomy at the University of Cambridge, and he joined us in August to talk about a space rock named “Oumuamua,” the theories that sprung up around it, and what happens when scarce data lead to wild speculation.

Plants have much to teach us (12/27, 1 p.m. CT)

Michigan State University professor Beronda L. Montgomery joined us in October to discuss what plants “know,” how they overcome obstacles, and what we humans can learn from them. Her book is called “Lessons From Plants.”

For centuries, doctors really didn’t understand the female body (12/28, 1 p.m. CT)

Elinor Cleghorn suffered through a long series of misdiagnoses before finally correctly being diagnosed with an autoimmune disease. She joined us in August to unpack the long history of how medicine has failed women, which she writes about in “Unwell Women: Misdiagnosis and Myth in a Man-Made World.”

Why people break up with their parents (12/29, 1 p.m. CT)

Joshua Coleman is a psychologist and senior fellow at the Council on Contemporary Families, and he joined us in March to talk about why parent-child bonds are easily severed in a modern family setting.

Anxiety can actually be good for you (12/30, 1 p.m. CT)

Dr. Wendy Suzuki is a professor of neural science and psychology in the Center for Neural Science at New York University, and she joined us in September to discuss how we can master stress to put it to good use. Her book is called “Good Anxiety: Harnessing the Power of the Most Misunderstood Emotion.”

There’s no danger in strangers (12/31, 1 p.m. CT)

Journalist Joe Keohane joined us in August to discuss the benefits of breaking down our silos and inclinations to isolate in order to find connection, empathy and a path to happiness. His book is called “The Power of Strangers: The Benefits of Connecting in a Suspicious World.”