At 104 acres, it would be rather small for a country, roughly the size of Vatican City — but the newest U.S. embassy is much more, a $700 million complex that is the largest and most expensive embassy ever built.

FOX News was granted exclusive first access to the embassy, a crowded set of 27 buildings in Baghdad where 1,200 staffers live and work. A titanic project years in the making, it's finally open for business.

Click here for an exclusive look inside the giant new embassy.

Since construction began on the new embassy in 2005, the U.S. mission has changed repeatedly, but officials in Baghdad say the structure represents the U.S. presence and its commitment to diplomacy, civil affairs and soft power.

"It symbolizes a move to a more normal relationship with the Iraqi government," said Susan Ziadah, U.S. Embassy spokeswoman, noting that Americans have now moved out of their old location in the Green Zone and returned it to Iraqis — though the new location is just a mile away.

Security experts are guarding workers with a number of careful measures, and the fortress-like compound is protected with bulletproof glass.

But with security in Iraq still not what it should be, in-house comforts for staffers are essential, and include a gym, recreation areas and a swimming pool.

"The people here have worked hard at creating a community for themselves," said Christian Lilley, community liaison officer at the embassy. And once the landscaping at the giant compound is taken care of, the place will look homier still.