Bob Poole Films Inside Of A Massive Sandstorm For National Geographic's 'Great Migrations' (VIDEO)

While filming the migrations of desert elephants in Mali, Africa, Bob Poole was thrust in the middle of one of Mother Nature's most incredible phenomena: a monstrous sandstorm.

The gigantic wall of sand rapidly approaches, stretching from horizon to horizon, and Poole realizes there's nowhere to run, so they "just kept rolling."

"The thing ran over us like a freight train," Poole says. The sandstorm blacked out the sun for four hours, eventually casting the landscape in an eerie red glow, as though they were visitors to an alien planet. "It's like the world came to an end," Poole tells the camera in the midst of the chaos.

The video comes via National Geographic's recently launched website for "Great Migrations." The feature is a seven-part series that travels 420,000 miles across 20 countries over the span of 2.5 years, capturing the momentous journeys that millions of creatures undertake to survive. Although "Great Migrations" doesn't premiere until November, the new website has plenty exclusive clips and behind-the-scenes footage to tide you over until then.