In June, President Barack Obama and his family visited some of the most beautiful national parks in the U.S. He talks about the importance of America's "national treasures" and the need to protect them. VOA Khmer's Seoung Sophat narrates.
"When I wrote the book and published it in 2000, 16 years ago, I did not expect that the Chinese would continue building dams at the rate that they have now done. So, the uncertain future has proved to be exactly that: very uncertain indeed," said Mekong Historian Milton Osborne.