President Abraham Lincoln signed the order to found the Secret Service and was shot hours later that same day.

However, Lincoln initially created the Service to combat the nation’s growing issue of counterfeit money, calling it the Secret Service Division of the Department of the Treasury. The agency wasn’t placed in charge of guarding presidents until after President McKinley’s assassination in 1901; the third president killed.

The Service’s responsibilities expanded in 1867 to combat "detecting persons perpetrating frauds against the government." This included smugglers, fraudsters, and even the KKK. The FBI eventually took over many of those responsibilities.

One year after being appointed presidential bodyguards, William Craig perished in a presidential carriage accident in 1902. He is the first of only two Secret Service members killed.

Leslie Coffelt became the only Secret Service member to die while actively protecting the president in 1950. During an attack on President Harry S. Truman in his residence by two Puerto Rican nationalists, Coffelt killed one attacker after being shot three times himself. He succumbed to his injuries, but successfully helped defend Truman.

The Secret Service bans the president from driving on all public roads for the rest of their lives after taking office.

The Secret Service is in charge of protecting the spouses and immediate family of 36 people, including the president, vice president, and more. The only exception occurs when a spouse remarries.

The night before Kennedy’s assassination, many of his Secret Service agents were out partying until 5am. However, it is doubtful that contributed to the day’s tragic events.

Ronald Reagan’s longtime Secret Service agent John Barletta recognized the extent of Reagan's Alzheimer's when the former president began needing help saddling up his horse. Later on, Reagan spent time raking leaves out of his pool, but Secret Service members often replenished them to keep him busy.

The president’s limo is known as Cadillac One. Once a Cadillac One has run its course, it is customary for the Secret Service to completely blow it up.