Eight great American discoveries in science

When the colonies declared independence from Great Britain in 1776, scientists in the Americas, with a few notable exceptions, were largely dependent on Europeans — shipping botanical specimens, for example, across the Atlantic for study and classification, according to Marc Rothenberg, the agency historian with the National Science Foundation. But in the 19th century, the infrastructure was put in place for homegrown American science and engineering.

“In the 20th century we really become an international leader,” Rothenberg said. Follow along as msnbc.com takes a look back at some of the achievements and discoveries that gave the U.S. a leadership role in the sciences.