Washington, D.C. is the United States of America’s capital city and, for many visitors, a place of knowledge and new discoveries. However, the institution which runs many of D.C.’s museums—the Smithsonian—may have just discovered something new, themselves.
While working on the National Mall’s Castle restoration project, a group of construction workers uncovered a secret, sealed underground chamber. But what is the purpose of this chamber and how might it change the capital as we know it?
Smithsonian Castle Restoration
The National Mall’s Castle has been closed since February 2023 for an extensive restoration. This restoration is called the Castle Revitalization Project and is the building’s first renovation in half a century.
The Castle was built in 1855 to house the Smithsonian Institution’s operations. (The Smithsonian Institution is named after British scientist James Smithson. Upon his death in 1829, he left a large endowment to the United States and asked that his fortune be used to facilitate “the increase and diffusion of knowledge among men.”)
Building the Castle
The Smithsonian Institution was established in 1846 by Congress as a public trust. The Smithsonian needed a home base that would fit the theme of gaining knowledge. Architect James Renwick Jr. crafted its impressive new headquarters in a style reminiscent of English Norman architecture. This style blends elements from the 11th and 12th centuries and combines early Romanesque and Gothic influences.
The castle is constructed from red sandstone sourced from Seneca Creek, Maryland. Over the years, the building has featured exhibition spaces, a library, chemical labs, storage rooms, and served as the office of the Smithsonian’s first secretary, Joseph Henry. The Castle quickly established itself as a central landmark on the National Mall, prompting the development of additional museums and government structures in its vicinity.
The Renovation Project
The Castle Renovation Project focuses on updating the Smithsonian’s historic headquarters by restoring and replacing its windows, roof, and utility systems. According to a 2023 statement from the institution, the iconic red stone exterior of the Castle will remain unchanged.
This renovation effort is designed to shed light on the evolution of infrastructure in the nation’s capital. By preserving the building’s exterior while upgrading its internal systems, the project aims to highlight the historical significance of the Smithsonian’s headquarters as well as to upgrade the building for ongoing use.
An Interesting Discovery
According to reporter Scott Thuman, the Castle Revitalization Project has brought a “huge amount of construction” to “one of D.C.’s most iconic buildings.” However, these construction workers may have just made an amazing discovery.
While renovating the Smithsonian Castle in Washington, D.C., workers have discovered an unexpected hidden chamber. But what was the purpose of this mysterious chamber?
Where the Chamber was Found
According to a statement made by the National Park Service, a group of construction workers found the chamber’s opening while working on utilities beneath Jefferson Drive.
Jefferson Drive goes through the National Mall. If it hasn’t already been clear, the National Mall is not a shopping mall—it is the capital’s iconic stretch of museums and memorials that includes the Smithsonian Institution Building, known as the Castle.
What is the Chamber?
According to the National Park Service, this recently discovered “secret chamber” measures 9 feet across and 30 feet deep. It was built in 1847.
The smooth brick walls were designed to capture and hold rainwater; this structure is called a cistern. Despite its purpose, the sealed-off chamber was found to be completely dry inside.
Secret Archives
This cistern, made for the purpose of storing water, is absolutely a genuine underground feature of D.C. However, for many years, there have been numerous myths about hidden structures beneath the National Mall.
According to Smithsonian magazine’s Jesse Rhodes and Eli Wizevich, rumors persist about an elaborate network of subterranean Smithsonian archives located under the Mall. Although these rumors are imaginative and intriguing tales, no such labyrinth of secret archives exists beneath the Mall.
(Somewhat) Mysterious Tunnels
Although there are no secret archives, there are actually a number of staff-only passageways under the Mall. One such tunnel connects the Castle to the National Museum of Asian Art’s Freer and Sackler galleries, the National Museum of African Art, and the Arts and Industries Building.
Additionally, there is a much more cramped tunnel between the Castle and the National Museum of Natural History. However, according to Smithsonian magazine, “most employees prefer a quick jaunt across the National Mall.”
An Intriguing Find
The National Park Service said, “Sadly, no national treasures or secret symbols were recovered” in the underground chamber. However, that doesn’t mean that this find isn’t interesting.
The NPS eloquently explained that “the cistern offers a neat glimpse into the museum’s and the National Mall’s past.” Although this intriguing and mysterious underground chamber is more of a brick-lined hole in reality, the US capital has only solidified itself as a great place to learn and explore.
