Stefan Krasowski had a dream: to visit every country on Earth before he turned 40. That dream took him around the world, from the crystal blue crater lakes of Djibouti and the ancient Roman ruins of Tunisia to the foothills of the Himalyas in Bhutan.

But as Krasowski's 40th birthday approached, there was just one country that eluded him: Syria.

When he found out last month that the country's tourism minister had approved his visa, he dipped into his considerable stockpile of credit card points and hopped on a plane.

President Trump will return to the world's biggest stage this week to address heads of state at a time when U.S. global leadership is seen as waning.

When he takes the stage at the United Nations General Assembly for the third time on Tuesday, Trump is expected to "affirm America's leadership role" and "underscore that America is a positive alternative to authoritarianism," said a senior administration official.

Iran's Foreign Minister Mohammad Javad Zarif says his country will not succumb to economic pressure by the Trump administration.

"We are resisting an unprovoked aggression by the United States," Zarif told NPR's Steve Inskeep in an interview in New York City on Sunday. "I can assure you that the United States will not be able to bring us to our knees through pressure."

Leaders from nearly 200 countries are attending a special United Nations Summit on climate change today, as they face increasing pressure from citizens around the world to cut global greenhouse gas emissions and slow global warming.

Currently, global emissions are on track to cause potentially catastrophic climate change in the coming decades.

For people who live with chronic pain, getting up, out and moving can seem daunting. Some fear that physical activity will make their pain worse. But in fact, researchers find the opposite is true: The right kind of exercise can help reduce pain.