This post has been updated.

Children describing the sounds bombs make as they fall. Streets covered with rotting garbage. Doctors and nurses who have gone months without pay, at hospitals struggling to care for an influx of cholera patients and malnourished infants.

That’s what FRONTLINE filmmaker Martin Smith and his team witnessed in May when they became the only foreign journalists given permission to enter Yemen, the country that’s home to what the United Nations recently called the “largest humanitarian crisis” in the world.

“People are not seeing what’s going on. We’re talking thousands of civilian dead,” Smith says in Inside Yemen, a documentary short released today by FRONTLINE.

Narrated by Smith, produced by Michelle Mizner and Sara Obeidat, and filmed by Scott Anger, Inside Yemen is a rare, up-close look at the consequences of two-plus years of airstrikes on the country by a Saudi-Arabia led coalition that has received weapons and tactical assistance from the United States.

“You have the region’s wealthiest country bombing the region’s poorest,” says Smith, whose trip to Yemen was part of his reporting for an upcoming FRONTLINE special on the rivalry between Saudi Arabia and Iran. Airing in 2018, the documentary will trace the roots of the Sunni-Shia divide, and explore how a proxy war between the two countries is devastating the Middle East.

Meanwhile, as the situation in Yemen continues to worsen (last month, the World Health Organization called the country’s cholera outbreak “the worst” in the world), scenes like those that unfold in Inside Yemen have become increasingly off-limits to journalists.