A new exhibit at HistoryMiami in downtown Miami explores the origins of mythical creatures such as mermaids, sea monsters, unicorns and even local creatures of lore like the Skunk Ape and Chupacabra.

Wading into a shallow river in the country of Georgia, scientists scanned the water for movement. Hidden among the tree roots, they caught a “yellowish” creature. It was a new species. Researchers ...