Secrets Underground

4:00 AM to 5:00 AM

Thursday 19 September

California's Hidden Doomsday

Season 1 Episode 6 of 8

Rob Nelson heads to California to investigate a network for major fault lines that could set off a mega-quake. Plus, he explores a mysterious sinkhole

Secrets Underground airs on Discovery Science at 4:00 AM, Thursday 19 September. (Subtitles.)

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