The United States originally had no permanent capital city. Congress met in eight different cities including New York, Philadelphia and Baltimore before 1791.

In 1790, Congress passed the Residence Act, establishing the permanent seat of government along the Potomac River on a site to be determined by the nation's first president, George Washington. He chose 10 square miles of land ceded by Maryland and Virginia. The southwest portion of that land would eventually be reabsorbed into Virginia and now makes up most of the city of Arlington.

Washington then chose three commissioners to survey the area. Those commissioners hired a French engineer, Pierre Charles L'Enfant, to plan the capital city and its government buildings. L'Enfant chose an elevated spot on what was then known as Jenkins' Hill for the nation's Capitol. The hill was “a pedestal waiting for a monument,” he said.

With a site selected, a contest was held in 1792 to design a new Capitol. That contest was won by William Thornton.

On Sept. 18, 1793, Washington crossed the Potomac River and was met by two brass bands, a volunteer artillery company and a delegation of Masons from Virginia and Maryland. They escorted the commander-in-chief to what is now Capitol Hill in what would be the not-yet-a-city's first parade.

Washington placed an inscribed silver plate beneath the cornerstone at the southeast corner of the building. After the completion of the Masonic ceremony, a celebration was held including a barbecue. Festivities continued until dark.

In 1800, Congress moved into the first section completed — what is now the Capitol's north wing. Seven years later, the House of Representatives moved into the south wing, which would still be under construction until 1811.

On Aug. 24, 1814, British troops invaded Washington and set fire to most of the city's federal buildings, including the Capitol. Only a freak rainstorm saved the building from total destruction. Congress would meet in temporary quarters for the next five years.

Physician, painter and inventor William Thornton won the 1792 contest to design a Capitol. His prize: $500 and a plot of land in the new city.

British soldiers set fire to the Capitol and other buildings in D.C. during the War of 1812, but architect Charles Bullfinch oversaw the completion of the Capitol and the addition of a new dome in 1826.

By the mid 19th century, the number of states had more than doubled, creating the need for a larger Capitol. Wings and a new cast iron dome — seen here at Abraham Lincoln's inauguration in 1861 — were completed by 1868.

The Capitol was considered completed in 1826, but just 24 years later, the number of states had more than doubled since 1793. Instead of 30 senators, there were now 62. Instead of 69 representatives, there were now 233.

Work was begun that year to expand the building with two new wings and a new cast iron dome. Work came to a halt in 1861, however, when the Capitol was used as a hospital and barracks for troops during the Civil War.

While preparing to celebrate the Capitol's centennial in 1893, historians began searching for the silver plate that Washington had laid beneath the cornerstone. They had no luck. In the 1950s, metal detectors were brought in, but again: No luck.

In 1991, Architect of the Capitol George White was researching source materials of the cornerstone laying when it dawned on him that the Alexandria Gazette — the newspaper that had covered the laying of the cornerstone — had reported it was laid at the southeast corner of the building.

Did that mean the southeast corner of what would be the first building to be completed — what was, at the time, the Senate wing — or the southeast corner of the entire building, most of which was to be built later? That would put it at the corner of what is now the House of Representatives' Statuary Hall.

This produced yet another excavation to search for the silver plate. And another disappointment.

The Library of Congress moved into its own building in 1897 and the Supreme Court moved into its own building in 1935. Today, the Capitol building is the centerpiece of a complex of six office buildings, three Library of Congress buildings, the Supreme Court Building and other facilities.

The Library of Congress moved into its own building in 1897 and the Supreme Court moved into its own building in 1935. Today, the Capitol building is the centerpiece of a complex of six office buildings, three Library of Congress buildings, the Supreme Court Building and other facilities.