This is the first in a 3-part series that offers an inside look at the FBI. FOX News was granted rare access for the reports, which examine the lives of bureau agents.

QUANTICO, Va. — The FBI has confronted many threats in its 100-year history, from busting gangsters in the '20s and '30s to hunting for Nazi saboteurs during World War II. But its newest recruits were in college or just out on Sept. 11, 2001, and they're being trained to tackle a new enemy.

"(Recruits) come in understanding that they can be sent to Islamabad, Pakistan as easily as to Indianapolis given the threats of the time," said Robert Mueller, director of the FBI.

Having celebrated its 100th anniversary in July, the bureau expects to graduate about 1,000 new agents this year alone. That's a significant number, as there are just 12,700 agents now.

• Click here to see photos of training exercises at Quantico.

For every recruit at the FBI Academy in Quantico, Va., there are 50 who applied for the five-month course. Most come to the bureau in their late 20's or early 30's. It's a second career for many of them, where they are taught everything from law and intelligence gathering to traditional skills like defensive tactics and making arrests.

"They push you to your physical limits, and that's how it should be," said a bureau recruit whose identity is being shielded for security reasons.

Click here to see more on training the next generation of FBI agents.

Though recruits still put in their hours at the firing range, the FBI is now focusing — some critics would say struggling — to recruit more candidates with specialized skills, including second or third languages to help deal with foreign threats.

But some civil liberties groups say they're concerned the bureau will rely on racial profiling. When FOX News visited Quantico, both arrest and interrogation scenarios included civilians playing roles as Muslim extremists.

One arrest scenario shown to FOX News was built around a Muslim bomb-making cell. Academy officials said it was to ensure that recruits are comfortable with a broad range of people.

"This exercise is about dealing with someone form a different culture," said FBI instructor Arnold Bellmer.

Despite the critics, Mueller insists the transition from fighting crime to fighting terrorism is possible.

"You can never underestimate the skills you pick up being on the street day in and day out, talking to people, questioning people — it's the same skill set that is necessary to prevent the next terrorist attack," said Mueller.

For many at the Academy, the training is what binds the next generation together.

"You build that camaraderie with the people around you," said a recruit. "That's why I believe the bureau is so strong. We are a family and it starts here."

For more in-depth reports on the FBI, check FOXNews.com for the next installments on the life of a career street agent and life after the FBI.