Alyson McGregor studies women's health, especially as it relates to emergency care -- when time-sensitive, life-or-death decisions are made using drugs and treatments mainly tested on men.

David Casarett asks: What if mainstream health care operated more like a medical marijuana dispensary?

Rishi Manchanda is an "upstreamist." A physician and public health innovator, he aims to reinvigorate primary care by teaching doctors to think about—and treat—the social and environmental conditions that often underly sickness.

As the leader of the Imaging Team on the Cassini mission to Saturn, Carolyn Porco interprets and shares the pictures coming back from this fascinating planet, its rings and its moons.

Joshua Klein is a fervent hacker of all things, including wet, pulpy systems like animals and people and the way they behave.

Think of Keith Barry as a hacker of the human brain -- writing routines that exploit its bugs and loopholes, and offering a revealing look at the software between our ears.

Petter Johansson and his research group study self-knowledge and attitude change using methods ranging from questionnaires to close-up card magic.

Cara E. Yar Khan is an international human rights advocate promoting the inclusion of people with disabilities within all facets of society.

With a deck of cards and authoritative cool, David Blaine brings the wonderment of magic off the stage and onto the sidewalk.

Katrina Spade created a system called "recomposition" that transforms human bodies into soil, so that we can return to the earth after we die.

Edith Elliott believes that the best solutions in global health are often the simplest — and the most overlooked.

Jonathan Marks works at the intersections of ethics, law and policy -- writing and speaking about torture, obesity, fracking, health care and other pressing issues of our time.

Eli Beer, the founder and president of United Hatzalah, has re-imagined first response by training EMT volunteers to respond to local calls and keep people alive until official help arrives.

Marc Koska wants to improve health care in the developing world by re-designing dangerous medical tools -- and offering education to practitioners in under-funded clinics.

William Ury is a mediator, writer and speaker, working with conflicts ranging from family feuds to boardroom battles to ethnic wars. He's the author of "Getting to Yes."

Elon Musk co-founded and leads Tesla, SpaceX, Neuralink and The Boring Company.

Sarah Rugheimer looks for signs of life on other planets by studying the telltale chemical signatures on distant planets.

From her base in India, Shweta Narayan works on accelerating the role of health professionals in climate action.

With a team of engineers, Paul Moller works on the Skycar, a combination car and jet, as well as the M200, a saucer-shaped hovering car. He also develops next-generation engines to power these and other amazing vehicles.

Agnes Binagwaho helped rebuild the Rwandan health care system and continues to fight for positive change in global health.

Mary Bassett is fighting what may be the greatest stumbling block to equitable health care in the US: institutional racism.

Eric Dishman does health care research for Intel -- studying how new technology can solve big problems in the system for the sick, the aging and, well, all of us.

Dr. Leana Wen is Baltimore City's Health Commissioner.

Using unexpected channels like the pulpit and the barber’s chair, Dr. Joseph Ravenell delivers basic health care information to an at-risk demographic -- African-American men.

At his lab at Stanford School of Medicine, Tony Wyss-Coray studies aging -- and potential cures for it.

At the intersection of word and form, Marian Bantjes makes her art.

Tim Guinee is a passionate advocate for creating a more sustainable world.

Halla Tómasdóttir is CEO of The B Team, a group of global business and civil society leaders driving a better way of doing business for the well-being of people and the planet.

Sarah Kay is a writer, performer and educator from New York City.

Driven by a fascination with the natural world, Victoria Gill believes we would all be happier if we knew the stories behind the organisms and materials we interact with every day.