
The hidden journey made by 20,000 zebras
CNN
Botswana's Nxai Pan National Park -- part of our planet's biggest expanse of salt pans -- is so isolated that the world's longest annual mammal migration, which crosses these pans, was not even documented until a decade ago.
(CNN) — The chopper rose smoothly from Maun Airport and we hurtled ahead over Thamalakane River. I knew it was a 'river' only because I could see a bridge -- there was nothing about the sandy ribbon of dust to suggest it had ever been touched by water.
It was hard to imagine that, just 30 kilometers (18.6 miles) away, the world's largest inland delta sprawled northwards, stretching beyond Namibia's Caprivi Strip border.
This is Botswana's Nxai Pan National Park -- part of our planet's biggest expanse of salt pans. It's an isolated region where the 600 square kilometers of Okavango Delta finally seeps away into the insatiable sands of the Kalahari Desert -- aptly known to early travelers as "the great thirstland."

The governments of Mexico and the United States signed a memorandum of understanding on Thursday to fund and expedite several wastewater treatment projects in the Tijuana River basin. Untreated wastewater continually affects residents living along the river, which flows across the border from Tijuana and through several of San Diego’s southern neighborhoods.