One day Zeus was spending time with some nymphs, including one of his favorite nymphs, Echo. Hera, who was about to discover Zeus with the nymphs, was delayed by Echo's incessant talking while the other nymphs fled. After Hera found out about the deception she punished Echo by only allowing her voice to repeat what was said to her. Later, Echo fell in love with Narcissus. Since Narcissus loved only himself, he spurned Echo's love. When the gods heard of Narcissus's treatment of Echo, he was condemned to forever contemplate his beauty in a reflection pool on Mount Helicon in Greece. He finally wasted away until the only thing left was a flower, called the narcissus. In time, Echo wasted away until only her voice remained.
Sounds
and Echoes:
Some sounds appear to not echo, such as a dog's bark, a duck's quack, etc. Mythbusters apparently proved that these sounds do echo but we cannot hear it. The laws of physics are still intact.