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Untold: The Invisible Tsunami That Killed 1,500 People in One Night

11 minutes 27 seconds

Now Playing As: Captioned (English) (change)

On August 21, 1986, violent explosions rocked Cameroon’s Lake Nyos. A wave of water over 15 meters high flattened vegetation along the southern shore, but a second deadly, nearly invisible wave of carbon dioxide blanketed the nearby towns, suffocating residents and animals. In this episode, host Alex Dainis investigates how a lake could explode and a gigantic wave of deadly carbon dioxide gas could escape. Part of "Untold" series.

Media Details

Runtime: 11 minutes 27 seconds

White background with faint gray grid lines with a physics equation breaking down P, E sub G or Pressure times Gravitational Potential Energy.
Untold
Episode 1
14 minutes 56 seconds
Grade Level: 7 - 12
Closeup of a woman with brown hair in a low braid wearing a black shirt standing on a sandy beach with a wooden ramp and ocean waves crashing behind her.
Untold
Episode 2
15 minutes 40 seconds
Grade Level: 7 - 12
Angled side view of a man with dark hair in a gray hoodie jacket with white corded headphones plugged into a smartphone armband on his arm. He runs along a pier on a foggy day with a city skyline in the background.
Untold
Episode 3
11 minutes 27 seconds
Grade Level: 7 - 12
Closeup of a plastic model of a city street corner with a brown-brick building. 2 men in overalls walk on the sidewalk in front of the building, and a woman in a gray apron walks on the street looking up at a thick brown liquid being poured onto the model in front of her.
Untold
Episode 4
13 minutes 11 seconds
Grade Level: 7 - 12
White background with gray grid lines. Title text in teal reads, "The electromagnetic spectrum." Underneath is a black line with waves getting tighter to the right, and a rainbow called, "visible light," highlighting a small portion of the line.
Untold
Episode 5
11 minutes 57 seconds
Grade Level: 7 - 12
Graphic of a dissected teal battery with a plus sign and text that reads, "positive electrode," at the top and a minus sign and text that reads, "negative electrode," at the bottom. Next to it is a green cylinder labeled, "electrolyte."
Untold
Episode 6
14 minutes 32 seconds
Grade Level: 7 - 12
Large blue machine rolling out 3 strips of metal into a long steel tube.
Untold
Episode 7
12 minutes 50 seconds
Grade Level: 7 - 12
Computer graphic of a sphere superimposed with an infrared heat signature on a black background. Most of the globe is bright green with the middle in dark blue and purple and small red spot with yellow shooting out toward the bottom center.
Untold
Episode 8
12 minutes 29 seconds
Grade Level: 7 - 12
White background with gray grid lines with a molecule diagram on it. Text underneath the diagram reads, "Amino acid."
Untold
Episode 9
13 minutes 51 seconds
Grade Level: 7 - 12
Pointy hill with traces of snow appears in front of a lake and other snowy hills in the distance. Green Northern Lights are visible in night sky over the distant hills.
Untold
Episode 10
12 minutes 42 seconds
Grade Level: 7 - 12
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