https://kaii-kiroku.com/en/case/1437
Periodic Low-Frequency Hum and Blueish-White Emanations in Cangandala National Park, Angola,...
At 23:40 on July 15, 2021, an unexplained low-frequency vibration and irregular bluish-white emanations were simultaneously observed deep within Cangandala...
cangandala national parklow frequencyperiodichumblueish