Half world heritage sites threatened by development say WWF

The Great Barrier Reef, the Inca city of Machu Picchu in Peru, they're just some of the world's most precious natural and cultural heritage sites, but they're under threat from industrial activity like never before.

That's the warning from the charity, the World Wildlife Fund.

It says half of the 229 world heritage sites could be at risk from development like logging, fishing and oil exploration.

Roger Harrabin reports.