Though an adult chimpanzee is significantly smaller than an adult gorilla, it has a penis about double that of the gorilla. An adult gorilla's penis is about 1.5 inches (4 cm) in length.

Sound travels up to 15 times faster through steel than air, at speeds up to 19,000 feet per second.

Over half of the world's geysers are found in Yellowstone National Park.

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