The pandemic spurred an unprecedented reclamation of urban space, ushering in a seemingly bygone era of pedestrian pastimes, as cars were sidelined in favor of citizens. Highlighting examples from across the United States, environmental designer Kevin J. Krizek reflects on how temporary shifts -- like transforming streets into places for dining, recreation and community -- can become permanent fixtures that make for more livable and sustainable cities.

China has pledged to be carbon neutral by 2060 -- and its citizens are helping industries across the country reach that goal. Environmentalist Ma Jun introduces the Blue Map, an app that empowers people to report pollution violations in their communities and track real-time environmental data, holding emitters accountable and helping companies along the global supply chain make informed sourcing decisions. Hear how the app uses the power of transparency to motivate more than 14,000 factories (so far) to clean up.

African artifacts shown in museums worldwide are often not borrowed, but stolen -- and TED Fellow Jim Chuchu is on a mission to get them back. Learn the sordid history behind how many of the collections in the West came to be, Chuchu's extensive work tracking and restoring Kenya's cultural heritage and what these efforts can mean for the wider African continent. An urgent call for institutions to reconsider the morality of the objects they "own" and their significance to the communities from which they were taken.

What if you were holding life-saving medicine ... but had no way to administer it? Zoom down to the nano level with engineer Kathryn A. Whitehead as she gives a breakdown of the little fatty balls (called lipid nanoparticles) perfectly designed to ferry cutting-edge medicines into your body's cells. Learn how her work is already powering mRNA-based COVID-19 vaccines and forging the path for future therapies that could treat Ebola, HIV and even cancer.

As COVID-19 spread, BioNTech cofounders Uğur Şahin and Özlem Türeci had one goal: to make a safe, effective vaccine faster than ever before. In this illuminating conversation with head of TED Chris Anderson, the immunologists (and married couple) share the fascinating story of how their decades of mRNA research powered the Pfizer-BioNTech vaccine -- and forecast what this breakthrough science could mean for the future of vaccines and other immunotherapy treatments.

Coming to us from 50 years in the future, legendary sci-fi writer Kim Stanley Robinson tells the "history" of how humanity ended the climate crisis and restored the damage done to Earth's biosphere. A rousing vision of how we might unite to overcome the greatest challenge of our time.

In the face of trauma, happiness is resilience: a revolutionary act of thriving despite all odds, rather than wilting or surrendering. Community organizer and activist Miracle Jones offers a heart-to-heart meditation on the role of joy as a form of radical resistance, survival and protection for Black folks in the US and across the world. A warm reminder to embrace the guiding light of hope in the presence of darkness.

Every human and natural system -- from oil extraction to the flight of a flock of starlings -- can be seen as a set of repeating patterns. These patterns can be disrupted for good or for bad, says Nigel Topping, the High Level Climate Action Champion for COP26, the UN's climate change conference set to take place in November 2021 in Glasgow, Scotland. He shares three rules of radical collaboration that could positively disrupt the patterns of the global economy and help humanity tackle the world's greatest threat: climate change.

Thousands of years in the making, the Olympics began as part of a religious festival honoring the Greek god Zeus in the rural Greek town of Olympia. But how did it become the greatest show of sporting excellence on earth? Educator Armand D'Angour explains the evolution of the Olympics. (Directed by Diogo Viegas, narrated by Addison Anderson, music by Cem Misirlioglu and Brooks Ball)

"What if I was to tell you that a game of peek-a-boo could change the world?" asks seven-year-old Molly Wright, one of the youngest-ever TED speakers. Breaking down the research-backed ways parents and caregivers can support children's healthy brain development, Wright highlights the benefits of play on lifelong learning, behavior and well-being, sharing effective strategies to help all kids thrive by the age of five. She's joined onstage by one-year-old Ari and his dad, Amarjot, who help illustrate her big ideas about brain science. (This TED Talk was produced in collaboration with Minderoo Foundation as an educational tool for parents and caregivers around the world and is supported by UNICEF.)