Photojournalist Jacquelyn Martin's images "inside the bubble" show provide a behind the scenes look at U.S. Secret Service agents at work protecting the life of President Barack Obama. Though in the spotlight for recent scandals, the agency has had a long, storied history of service working in the shadows anonymously, tasked with protecting America's presidents and their immediate families.

Secret Service agents ride in the Osprey taking the traveling press back to Air Force One after attending President Obama's speech by the Edmund Pettus Bridge in Selma, Alabama on the 50th anniversary of "Bloody Sunday," a landmark event of the civil rights movement, Saturday, March 7, 2015.

Secret Service agents dot the tarmac as President Barack Obama (back right), salutes as he exits the Marine One helicopter to board Air Force One at Andrews Air Force Base, Maryland en route to Delaware where he is expected to visit the site of the damaged I-495 bridge in Wilmington to speak about transportation and infrastructure, July 17, 2014.

The agency celebrated its 150th birthday this past July.

With the Golden Gate Bridge in the background, Secret Service Agents guard the Marine One helicopter where President Barack Obama will leave Crissy Field Landing Zone in San Francisco, to attend a fundraising event in Los Altos Hills, California, during his three-day West Coast trip to Seattle, San Francisco and Los Angeles, July 23, 2014.

AP staff photographer Jacquelyn Martin is one of the photographers who cover the White House regularly and is also part of the traveling press corps. Her fascination with what she described as the service's "visual alphabet of dark suits, sunglasses and earpieces" and the agency's "intricate choreography... as they stay vigilant against all threats" drew her to train her eye on them.

A Secret Service Agent is seen through tinted and patterned glass as he stands in front of the door to a room where President Barack Obama was meeting with leading CEOs to discuss ways to promote the economy and create jobs during his last two years in office, at the Business Roundtable Headquarters in Washington, December 3, 2014.

Secret Service agents keep on the lookout for trouble as President Barack Obama takes an impromptu walk down 15th Street in Denver after having dinner at Wazee Supper Club, July 8, 2014. Obama was set to speak about the economy.

Despite the agency's troubles the men and women who serve as agents continue to put themselves in harms way, committed to taking a bullet if need be, for the safety of the president of the United States.

Fortunately, few Secret Service personnel have been shot in the line of duty. Special Agent Tim McCarthy did take a bullet in the chest after throwing himself between President Ronald Reagan and potential assassin James Hinckley Jr on March 30, 1981.

Secret Service agents watch the perimeter near an irrigation system as President Barack Obama tours a farm in Los Banos, California, where drought has been effecting the area, February 14, 2014.

They go where the president and the first family go. In high pressure and dangerous jobs, agents serve long hours away from their families and homes.

U.S. Secret Service agents from the Counter Sniper Division work on top of the West Wing of the White House, as seen from the Eisenhower Executive Office Building in Washington, December 11, 2014.

Secret Service agents swirl around President Barack Obama as he waves goodbye after speaking at the Congressional Hispanic Caucus Institute's 37th Annual Awards Gala at the Walter E. Washington Convention Center, in Washington, October 2, 2014.

After Robert F. Kennedy's assassination in 1968, Congress authorized the Secret Service to protect major presidential and vice presidential candidates. Then Senator Obama received protection earlier than any presidential candidate, nine months before voting in the Democratic primaries. Though the reason wasn't detailed, many assumed it was because of the historic nature of his run for the White House and the prospect of becoming the first black president. Usually protection is provided only once someone becomes the party's nominee.

A Secret Service agents works by the motorcade as President Barack Obama has dinner with winners of a DSCC "Dinner With President Obama" contest at Joe's Seafood, Prime Steak & Stone Crab, in Washington, October 1, 2014.

President Barack Obama, left, greets people as he is watched by a Secret Service Agent, at right, inside the Charcoal Pit in Wilmington, Delaware before speaking about transportation and infrastructure, July 17, 2014.

Police and Secret Service agents control the crowd as President Barack Obama takes an impromptu walk down 15th Street in Denver after having dinner at Wazee Supper Club, July 8, 2014.