If you're wondering why blackface -- mimicking people of African descent via stereotypes and makeup-darkened skin -- is a big deal, then perhaps a little history lesson can help demystify the outcry. Dwan Reece, curator at the National Museum of African American History and Culture, explains how this practice permeates the American psyche and culture (in theater, music, books and beyond) and why it's not simply harmless fun, but a legacy of oppression.

The seemingly mundane electronics you use every day -- your stove, dishwasher, TV and much more -- have a cumulative effect on the climate, says Best Buy's director of environmental affairs Tim Dunn. He shares how the company is helping people reduce their carbon impact through energy-efficient products, considering the full life cycle of everything they sell and designing for circularity -- as well as their commitment to get to net-zero by 2040.

From "got milk?" to "avocados from Mexico," marketing influences what you eat more than you may realize. But despite the known power of food marketing, farmers in Africa are more likely to receive funding for seed and fertilizer than they are for advertising geniuses. Agricultural development expert Zoë Karl-Waithaka outlines three ways industry, governments, NGOs and others can help African farmers improve their livelihoods -- and positively impact society, the economy and the environment.

Over the last two decades, the wind power industry has grown at a dizzying pace. (Fun fact: a single rotation from one of the world's most powerful wind turbines can generate enough electricity to charge more than 1,400 cell phones.) Building off this exponential growth, Denmark's climate minister Dan Jørgensen lays out his plan to end the country's oil industry by 2050 and transition to a fossil-free future powered by wind energy.

Could we use the energy from light and sound to detect disease? TED Fellow Lei Li shares the exciting promise of photoacoustic imaging: an affordable, painless and accurate method of converting light into sound in order to create high-resolution images of what's going on inside our bodies. From early detection of breast cancer to steering medicine-delivering micro-robots, learn how this cutting-edge technology could open up a new world of possibility when it comes to seeing, tracking and diagnosing disease.

In an engaging, insightful conversation, criminal justice reformer Nick Turner breaks down the ways the US criminal legal system perpetuates centuries-old racial and economic inequality. He joins TED current affairs curator Whitney Pennington Rodgers to outline why the best way to actually deliver justice and safety is to shrink the system and recognize the humanity of those caught in it.

Consent can be a tricky topic to talk about in sex education curriculums, but it doesn't have to be. In this hilarious and relatable talk, sex educator and TED Fellow Kaz offers a fresh look at teaching young people about the core principles of consent -- and shows how demystifying this topic leads to healthier and more satisfying relationships for people of all ages.

Buildings are bad news for the climate -- the indoor spaces we spend most of our lives in emit 40 percent of the world's greenhouse gases. Rethinking how to create and occupy the spaces we inhabit, Katie McGinty, chief sustainability officer at Johnson Controls, walks us through smart, efficient and eco-friendly ways to decarbonize buildings -- and the benefits to both business and the planet.

"The way we cool things down is heating the planet even more," says sustainable development expert Rachel Kyte -- and the solutions go well beyond just fixing air-conditioning. She identifies four major areas with transformative solutions -- from roofs painted with bright white paint to solar control glass to more efficient cold chains for vaccines -- that can be implemented in fair and sustainable ways. Learn more about what a community designed for cool could look like.

Short-sightedness may be the greatest threat to humanity, says conceptual artist Katie Paterson, whose work engages with deep time -- an idea that describes the history of the Earth over a time span of millions of years. In this lively talk, she takes us through her art -- a telephone line connected to a melting glacier, maps of dying stars – and presents her latest project: the Future Library, a forested room holding unread manuscripts from famous authors, not to be published or read until the year 2114.