Video: Technology

Mega-canyon discovered beneath Greenland ice sheet (1:04) 

Aug. 29 - Scientists using ice-penetrating radar have discovered a previously unknown canyon beneath the ice sheet in northern Greenland. They say the canyon is at least 750km long and in places as much as 800m deep and is on the same scale as parts of the Grand Canyon in Arizona, USA. Matthew Stock reports. ( Transcript )

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