The capital city of Washington , D.C . is home to many famous museums in the United States .
But there is one museum in the city that visitors will never get to see : the U.S . Secret Service Museum .
Placed inside the agency's headquarters , the one-room museum shows objects from the agency's history .
It also honors the 40 men and women of the service who have died while performing their duty .
Mike Sampson is a historian and archivist at the U.S . Secret Service .
He said the museum is only open to agency workers , their families , and some special guests .
He added that concerns about security and lack of resources are the reasons the museum is closed to other visitors .
The Secret Service is probably best known for protecting U.S . presidents .
But its first mission was to fight financial crime .
Jason Kendrick is another historian and archivist at the U.S . Secret Service .
It was not until 1901 , after the assassination of President William McKinley , that the Secret Service added the job of protecting the president .
But the service's work had expanded before then to fighting other kinds of crime .
One reason is that other agencies , such as the Federal Bureau of Investigation and the Central Intelligence Agency , did not yet exist .
The Secret Service fought against activities such as illegal trade , crimes relating to land ownership , and spying .
Kendrick explained that beginning in 1868 , the Secret Service was permitted to fight any crime against the federal government .
Some exhibits in the museum show examples of counterfeiting .
Now , the service also protects candidates for president , visiting heads of state , important foreign visitors , and special events related to national security .
It also continues to fight financial crime and fight against school violence and other attacks .
Working those duties sometimes comes at a price for Secret Service members .
Sampson says this part of the museum is a way to respectfully honor those Service members .
The museum , Sampson said , “gives us an opportunity to reflect on the history of our agency , and also to show what we're doing these days .”