National

Journalist Charlie Savage of the Boston Globe just won a Pulitzer Prize for national-affairs reporting. In an April 2006 article, he detailed how often President Bush has used "signing statements" to assert the right to bypass provisions of new laws; Savage's article prompted Sen. Arlen Specter (R-PA) to call for hearings investigating the matter. Rebroadcast from May 9, 2006.

It's not easy to track down one of the fastest and rarest great cats in the world. But one biologist is working to attach radio collars to cheetahs living in remote areas of Iran. With fewer than 100 of the animals left, they are among the most imperiled great cats on Earth.

It's not easy to track down one of the fastest and rarest great cats in the world. But one biologist is working to attach radio collars to cheetahs living in remote areas of Iran. With fewer than 100 of the animals left, they are among the most imperiled great cats on Earth.

Biologist George Schaller is the first to survey wildlife in Tibet's remote Chang Tang reserve in the winter. Schaller spoke with Alex Chadwick about some surprising findings from his 1,000-mile journey.

Biologist George Schaller is the first to survey wildlife in Tibet's remote Chang Tang reserve in the winter. Schaller spoke with Alex Chadwick about some surprising findings from his 1,000-mile journey.

Snow leopards are among the world's most endangered big cats, with only several thousand left. In Mongolia's southern Gobi desert, the snow leopard is a sign of a healthy ecosytem. But poaching remains one of the area's more lucrative businesses.

Snow leopards are among the world's most endangered big cats, with only several thousand left. In Mongolia's southern Gobi desert, the snow leopard is a sign of a healthy ecosytem. But poaching remains one of the area's more lucrative businesses.

A settlement once home to hundreds has been unearthed near England's Stonehenge. Archaeologists think the builders of the huge stone circle may have lived in the village. It dates to the same time period.

A settlement once home to hundreds has been unearthed near England's Stonehenge. Archaeologists think the builders of the huge stone circle may have lived in the village. It dates to the same time period.

The Asian tsunami of 2004 killed more than 170,000 people in the Indonesian province of Aceh alone, washing away tens of thousands of homes, schools and businesses. Two years later, reconstruction is under way, but serious challenges in housing and infrastructure remain.