Underground Layers of the US Capitol Building and The Missing Cornerstone

The US Capitol Visitor Center was the largest addition ever made to the Capitol Building in Washington, D.C. The CVC building, 50 feet underground, fronts the entire east side of the Capitol. The Capitol itself encompasses 775,000 SF, while the completed CVC contains 580,000 SF on three levels. Initial construction of the Capitol Building began in 1793. Below is some interesting photos/information I came across and thought more people should know:

The United States Capitol Visitors Center involved underground construction of offices, a visitor’s center, and additional space on the east side of the existing capitol building. Construction of the CVC required installation of a slurry diaphragm wall within two feet of the existing spread footings for the building and excavating to average depths of about 50 feet with maximum local excavation depths of up to 75 feet with no movement of the Capitol.

But the most interesting part after all this excavation; the missing cornerstone was still not discovered. But the reason why I did a post and uploaded these images of the capital building is; that it’s not clear if this underground structure was built originally with the building? But this also rings my ears to the mud flood… But that’s another post. Now to the mystery of the cornerstone from George Washington:

The United States Capitol cornerstone laying was the ceremonial placement of the cornerstone of the United States Capitol on September 18, 1793. The cornerstone was laid by president of the United States George Washington, assisted by the Grand Master of Maryland Joseph Clark, in a Masonic ritual.

(Below Quoted Article From Sept. 17, 1993) However, there is a problem: Nobody is sure where the stone is.

In a city where history reigns, it’s hard to believe leaders have lost the Capitol cornerstone. On the other hand, in a city where government has often been charged with wrongheadedness and confusion, maybe it isn’t so surprising.

There is a 1873 bronze plaque embedded on a wall in the lower level of the Capitol that deceptively boasts: “Beneath this tablet the cornerstone of the United States of America was laid by George Washington.”

For decades people were content to trust in American forebears and believe that the cornerstone rested below this plaque.

“Everybody has always just assumed that that’s where it was and that’s where we were looking,”said George White, the Capitol architect.

But excavations in the late 1950s, when the Capitol’s foundations were underpinned for new construction, proved this claim false. After exposing the building’s foundations, a metal detector was used to search for the silver plate buried with the cornerstone, but neither the silver nor the stone was found in the purported resting place.

Three years ago, White began to hunt for the cornerstone after an engineer became possessed by the mystery.

“He just became interested in looking for it and and started, on his own time, just scratching around thinking maybe he’d find it,” White said. “When I learned about that I said, `Well that’s not a bad idea, but we ought to do something more organized.’ “

In the fall of 1991, White asked members of the U.S. Geological Survey to use the latest and least invasive technology to search for the stone a second time. The survey team tested the soil for traces of silver that might have leached from the plate into the ground over the two centuries, but still there was no hint of a cornerstone in the area beneath the plaque.

To unravel the mystery, the Capitol staff turned to the archives. From the minutes of an 18th Century meeting, William Allen, the Capitol’s architectural historian, realized that people had been looking for the cornerstone in the wrong place.

When the original Capitol was first constructed, before being burned by the British in 1814, only the House and the Senate chambers existed and an outdoor walkway connected the two buildings where today’s central dome stands. Because the Senate chamber was built first, historians believed that the cornerstone was laid in the southeast corner of this building.

However, Allen discovered that the foundation for both chambers was laid at the same time, meaning that the southeast corner was not under the Senate chamber, but more likely under the House chamber to the south of the Senate.

Again, the U.S. Geological Survey was called in, but this time it excavated under the House chamber. In a 3-foot deep, unmarked pit near the House coffee shop, underneath the bustling tourists a floor above, White believes the team may have uncovered the missing stone.

“It looks like it was prepared for a ceremony,” White said. “It’s a big flat chunk of stone that weighs several tons by our estimates, from its size and composition, and it’s not something you’d be casual about.”