After President James K. Polk signed the legislation creating the Smithsonian Aug. 10, 1846, one of the first tasks facing its governing body, the Board of Regents, was to erect a building to house the new Institution. Less than nine months later, the cornerstone of the Smithsonian Institution Building, now called the Castle, was laid May 1, 1847. The day was declared a holiday, and a mile-long parade made its way from City Hall to the White House, where the President joined the procession before it continued to the Smithsonian grounds. Once there, more than 6,000 people watched as the cornerstone was laid. This photograph was taken in 1850 during the Castle’s construction and is the earliest-known image of the building. It shows the two completed wings of the building: The east wing housed the lecture hall, laboratories and home for the Secretary of the Smithsonian; the west wing contained the library and the

Read More: Earliest known photograph of Smithsonian Castle goes on display to celebrate institution’s 169th birthday