JUDY WOODRUFF:

Now we turn to the grinding civil war in Yemen, which has also become a proxy conflict between neighboring Saudi Arabia and Iran.

A two-and-a-half-year bombing campaign has killed thousands. Vast swathes of the country lie devastated. Compounding the horror, Yemen is on the brink of famine. There are critical shortages of aid and medical care, and now an outbreak of cholera is spreading.

The country has been essentially closed to journalists for months, but filmmaker Martin Smith and his team from Frontline were able to gain access to Yemen in May.

Frontline has a short film on its website documenting what they saw.

Here is an excerpt, beginning in the capital, Sanaa.