Here's a look at what goes into protecting the president on Inauguration Day
Keeping a president out of harm's way is a monumental task.
The upcoming inauguration for president-elect Donald Trump will pose unique challenges for the Secret Service.
The parade route Trump's motorcade will follow after the swearing-in ceremony stretches 15 city blocks from the U.S. Capitol to the White House.
The roughly two-mile trip down Pennsylvania Ave., according to retired Secret Service agent Joseph Funk, is so nerve racking it takes a toll on an agent's mind like no other assignment.
“You have the whole world watching, you have the leader of the free world, what better time to make a statement,” he said.
Planning for the inauguration changes little over the course of four years. What does change is the emerging threats, like the deadly terror attack on a market in Berlin earlier this month - which was carried out with a truck as the main weapon.
To counter, law enforcement will strategically stage garbage trucks and buses to block access to the president's procession and the hundreds of thousands of people expected to line the National Mall - similar to the security measures observed during the Macy's Thanksgiving Day Parade.
"The Secret Service does a lot of what 'ifs.' That’s all they do a lot of time is, 'what ifs,'" Funk said.
There are so many "what ifs" right now from lone wolf attacks to deepening concerns about the movement of groups, Funk estimates 15 to 20 thousand security experts from multiple agencies will assist in securing inauguration day Jan 20.
An added stress for Secret Service agents, given Trump's flair for the unpredictable.
“Will he get out where the Secret Service dictates or will he get out where he wants to get out?” Funk asked.
His advice to the president-elect? Listen to the Secret Service.