Phyllis Rodriguez and Aicha el-Wafi have a powerful friendship born of unthinkable loss. Rodriguez' son was killed in the World Trade Center attacks on September 11, 2001; el-Wafi's son Zacarias Moussaoui was convicted of a role in those attacks and is serving a life sentence. In hoping to find peace, these two moms have come to understand and respect one another.

With the same humor and humanity he exuded in An Inconvenient Truth, Al Gore spells out 15 ways that individuals can address climate change immediately, from buying a hybrid to inventing a new, hotter "brand name" for global warming.

In this brand-new slideshow (premiering on TED.com), Al Gore presents evidence that the pace of climate change may be even worse than scientists recently predicted. He challenges us to act.

The "dismal science" truly shines in this optimistic talk, as economist Alex Tabarrok argues free trade and globalization are shaping our once-divided world into a community of idea-sharing more healthy, happy and prosperous than anyone's predictions.

Alisa Miller, head of Public Radio International, talks about why -- though we want to know more about the world than ever -- the US media is actually showing less. Eye-opening stats and graphs.

HIV is a serious problem in the DR Congo, and aid agencies have flooded the country with free and cheap condoms. But few people are using them. Why? "Reformed marketer" Amy Lockwood offers a surprising answer that upends a traditional model of philanthropy. (Some NSFW images.)

Andy Hobsbawm shares a fresh ad campaign about going green -- and some of the fringe benefits.

Pop quiz: When does learning begin? Answer: Before we are born. Science writer Annie Murphy Paul talks through new research that shows how much we learn in the womb -- from the lilt of our native language to our soon-to-be-favorite foods.

If you've been in a restaurant kitchen, you've seen how much food, water and energy can be wasted there. Chef Arthur Potts-Dawson shares his very personal vision for drastically reducing restaurant, and supermarket, waste -- creating recycling, composting, sustainable engines for good (and good food).

One of a dozen Pakistanis who came to TEDIndia despite security hassles entering the country, TED Fellow Asher Hasan shows photos of ordinary Pakistanis that drive home a profound message for citizens of all nations: look beyond disputes, and see the humanity we share.

Ashraf Ghani's passionate and powerful 10-minute talk, emphasizing the necessity of both economic investment and design ingenuity to rebuild broken states, is followed by a conversation with TED curator Chris Anderson on the future of Afghanistan.