Authorities on alert this 4th of July

While the crowd's top concern will be taking in the fireworks, intelligence teams are hoping all is quiet--at least, on their end.

And to help ensure that, expect to see a large police presence supported by countless officers and agents you won't see.

Though federal law enforcement sources tell ABC7 that they're not facing any specific threats this fourth, they are prepared.

Among the greatest worries is radicals who've actually trained overseas, often in Yemen, or homegrown terrorists looking to make their mark.

"Regardless of if it actually materializes or happens or not, the fact that we get these warnings proves that the system works,” says Falls Church resident John Edwards.

It’s a system here that will combine the MPD, FBI, Park Police and more.

"There's always a concern during national holidays in the United States for the following reason, it's symbolic to extremist groups, so to launch an attack and be successful on that day would be a big deal for them,” says former FBI agent Brad Garrett.

Which is why New York and other major cities are also staying vigilant.