"Save the snail darter."

A snail darter is a small fish native to East Tennessee that was discovered in 1973. The construction of the Tellico Dam was stalled because of concerns that it would destroy the species, which was originally only present in the Little Tennessee River. The snail darter was declared an endangered species in 1975, but two years later an exemption gave permission for the Tellico Dam to be constructed. The snail darter was introduced successfully into the Hiwassee River, which flows through Georgia, North Carolina and Tennessee and in 1984 its status was lowered to threatened.

Read more about the fish 'only as big as a paper clip' that stopped the construction of a Dam.