TED Talks Daily

Want to help map the world? Community builder Rebecca Firth explains how the Humanitarian OpenStreetMap Team (HOT) is using open-source software powered by volunteers to put one billion people on the map in the next five years. (This ambitious plan is a part of the Audacious Project, TED's initiative to inspire and fund global change.)

Hannah Brencher's mother always wrote her letters. So when she felt herself bottom into depression after college, she did what felt natural -- she wrote love letters and left them for strangers to find. The act has become a global initiative, The World Needs More Love Letters, which rushes handwritten letters to those in need of a boost.

Consider the following scenario: a highly infectious, sometimes deadly respiratory virus infects humans for the first time. It spreads rapidly worldwide, and the WHO declares a pandemic. The death toll starts to rise and everyone is asking the same question: when will the pandemic end? Alex Rosenthal details the three main strategies governments can use to contain and end a pandemic. [Directed by Visorama, narrated by Jack Cutmore-Scott, music by Bamm Bamm Wolfgang].

What can you hear in silence? In this exploration of sound, host of the podcast "Twenty Thousand Hertz" Dallas Taylor tells the story of arguably the most debated musical composition in recent history -- composer John Cage's iconic piece 4'33" -- and invites you to take notice of the soundscape around you. Watch to the end to experience a performance of 4'33''.

At age 16, journalist and filmmaker Jose Antonio Vargas found out he was in the United States illegally. Since then, he's been thinking deeply about immigration and what it means to be a US citizen -- whether it's by birth, law or otherwise. In this powerful talk, Vargas calls for a shift in how we think about citizenship and encourages us all to reconsider our personal histories by answering three questions: Where did you come from? How did you get here? Who paid?

We have archives of films, newspapers, even seeds -- what if we could make one for the entire surface of the earth? Drawing on his experience mapping an ancient city in the Honduran jungle, archaeologist Chris Fisher makes the case for scanning the whole planet with LiDAR -- a technology that uses lasers shot from an airplane to map the ground -- in order to preserve our cultural and ecological heritage.

"In a world" -- our world -- movie trailers have undergone a massive evolution. The booming voice-of-God narration of the '80s and '90s has been silenced in favor of boojes and bwaas. In this episode of Twenty Thousand Hertz, host and sound design expert Dallas Taylor is joined by guests who share the history of trailers and a hilarious takedown of the sounds and dialogue that are common in the modern trailer style. You'll never be able to watch a blockbuster trailer the same way again. Twenty Thousand Hertz, a podcast revealing the stories behind the world's most recognizable and interesting sounds, is a new member of the TED family of podcasts. Listen or subscribe wherever you get your podcasts.

In a talk about understanding and practicing the art of healthy relationships, Katie Hood reveals the five signs you might be in an unhealthy relationship -- with a romantic partner, a friend, a family member -- and shares the things you can do every day to love with respect, kindness and joy. "While love is an instinct and an emotion, the ability to love better is a skill we can all build and improve on over time," she says.

Want to learn a new language but feel daunted or unsure where to begin? You don't need some special talent or a "language gene," says Lýdia Machová. In an upbeat, inspiring talk, she reveals the secrets of polyglots (people who speak multiple languages) and shares four principles to help unlock your own hidden language talent -- and have fun while doing it.

As kids, we all get advice from parents and teachers that seems strange, even confusing. This was crystallized one night for a young Clint Smith, who was playing with water guns in a dark parking lot with his white friends. In a heartfelt piece, the poet paints the scene of his father's furious and fearful response.