NARA was established in 1934 and is currently celebrating its 75th anniversary; a photo gallery of its history as an institution is available online. Among the many millions of documents that it preserves are the Charters of Freedom: the Declaration of Independence; the Constitution of the United States; and the Bill of Rights. A sense of the scope of other holdings can be had from the online subject index. Although its holdings are vast, only an estimated 1-3% of government records are held by NARA, and of these records, only a fraction is available in electronic form.
Agency-specific collections include, among many others: Records of the National Institutes of Health; Records of the Health Resources and Services Administration; Records of the Environmental Protection Agency; Records of the Food and Drug Administration; Records of the Public Health Service; and Records of the Indian Health Service.
The picture above shows President Herbert Hoover on February 20, 1933 at the ceremony for the laying of the cornerstone of the National Archives Building. The ceremony was accelerated to ensure that Hoover, who had just two weeks remaining in his term, would have his name on the cornerstone.