How often do you think about the air you're breathing? Probably not enough, says entrepreneur and TED Fellow Romain Lacombe. He introduces Flow: a personal air-quality tracker that fits in your hand and monitors pollution levels in real time. See how this device could help you track and understand pollution street by street, hour by hour -- and empower you to take action to improve your health.

At the center of a galaxy more than 55 million light-years away, there's a supermassive black hole with the mass of several billion suns. And now, for the first time ever, we can see it. Astrophysicist Sheperd Doeleman, head of the Event Horizon Telescope collaboration, speaks with TED's Chris Anderson about the iconic, first-ever image of a black hole -- and the epic, worldwide effort involved in capturing it.

The heart is one of the least regenerative organs in the human body -- a big factor in making heart failure the number one killer worldwide. What if we could help heart muscle regenerate after injury? Physician and scientist Chuck Murry shares his groundbreaking research into using stem cells to grow new heart cells -- an exciting step towards realizing the awesome promise of stem cells as medicine.

Bacteria "talk" to each other, sending chemical information to coordinate attacks. What if we could listen to what they were saying? Nanophysicist Fatima AlZahra'a Alatraktchi invented a tool to spy on bacterial chatter and translate their secret communication into human language. Her work could pave the way for early diagnosis of disease -- before we even get sick.

Bees are dying off in record numbers, but ecologist Noah Wilson-Rich is interested in something else: Where are bees healthy and thriving? To find out, he recruited citizen scientists across the US to set up beehives in their backyards, gardens and rooftops. Learn how these little data factories are changing what we know about the habitats bees need to thrive -- and keep our future food systems stable.

Phil Plait was on a Hubble Space Telescope team of astronomers who thought they may have captured the first direct photo of an exoplanet ever taken. But did the evidence actually support that? Follow along as Plait shows how science progresses -- through a robust amount of making and correcting errors. "The price of doing science is admitting when you're wrong, but the payoff is the best there is: knowledge and understanding," he says.

The Earth and Moon are like identical twins, made up of the exact same materials -- which is really strange, since no other celestial bodies we know of share this kind of chemical relationship. What's responsible for this special connection? Looking for an answer, planetary scientist and MacArthur "Genius" Sarah T. Stewart discovered a new kind of astronomical object -- a synestia -- and a new way to solve the mystery of the Moon's origin.

In 2013, a treasure trove of unusual fossils were uncovered in a cave in South Africa, and researchers soon realized: these were the remains of a new species of ancient humans. Paleoanthropologist Juliet Brophy takes us inside the discovery of Homo naledi, explaining how this mysterious ancestor is forcing us to rethink where we come from -- and what it means to be human.

In 2013, a treasure trove of unusual fossils were uncovered in a cave in South Africa, and researchers soon realized: these were the remains of a new species of ancient humans. Paleoanthropologist Juliet Brophy takes us inside the discovery of Homo naledi, explaining how this mysterious ancestor is forcing us to rethink where we come from -- and what it means to be human.

Gene-editing tools like CRISPR enable us to program life at its most fundamental level. But this raises some pressing questions: If we can generate new species from scratch, what should we build? Should we redesign humanity as we know it? Juan Enriquez forecasts the possible futures of genetic editing, exploring the immense uncertainty and opportunity of this next frontier.