There is a security nightmare is looming for the Big Apple as the New York City Marathon kicks off this weekend.
Read: How the NYC Terrorist Turned Scenic Bike Path Into a War Zone
More than 51,000 runners and 2 million spectators are expected at the marathon, which is a potential target for terrorists. The route snakes through all five boroughs of the city for 26.2 miles ending in Central Park.
Terrorism expert Bob Strang discussed the difficulties.
"This is like the perfect storm," he said. "You will see police officers on every corner. You will see officers on every rooftop. You will see K-9 units. You will see plain clothes cops. This is a full court press."
Some of the runners are not fazed by what is happened.
"I put my trust in them," one athlete participating in the marathon told Inside Edition.
Meanwhile, the route where the tragedy unfolded Tuesday has reopened, and people are back to jogging and running along the path.
Read: School Bus Driver Praised for 'Doing His Best to Take Care of Those Kids' in NYC Terror Attack
There are calls for steel bollards to be erected along the bike path for protection.