Pearl Harbor and Hickam Air Force Base have been close but distant neighbors for decades.

But beginning today, the two sites will cease to be separate bases, merging into Joint Base Pearl Harbor-Hickam. They will be among 26 installations across the country that are combining to form 12 joint bases as the military strives to become more efficient.

Commanders are bringing together two very distinct military service cultures—while making sure one doesn't dominate or overwhelm the other.

A chain-link fence divides the two properties, even though the only people they're keeping out are other military personnel. In 1975, the Navy even built a sentry post from where guards screened those crossing between the bases. Today, sailors and airmen will take down part of the fence in a symbolic ceremony.

The decision to join the two bases dates to 2005, when an independent panel on military bases recommended they merge. The commission recommended similar unions across the country to save money and create a more efficient military. In some cases, many of these bases aren't next-door neighbors. In Alaska, for example, Elmendorf Air Force Base and the Army's Fort Richardson are combining.

About 4,500 of the military and civilians working on the two bases—less than 10 percent of a total work force numbering 50,000—have jobs in departments that will be combining. The new base doesn't plan any layoffs. It would eliminate positions only by not replacing employees who retire or quit.

The base will likely even see a net increase of some 5,500 personnel in coming years as the Navy shifts new Virginia-class submarines to Hawaii and the Air Force brings in F-22 fighter jets and the Global Hawk unmanned surveillance aircraft.

Both bases also encompass multiple historic landmarks from the 1941 Japanese attack on both Pearl Harbor and Hickam.

There's the old barracks at Hickam that still displays holes from machine-gun bullets Japanese airmen fired during the attack. The building now houses the Air Force's headquarters for the Pacific region. It's not far from a distinctive water storage tower, called the Freedom Tower, that Japanese pilots avoided shooting at because they thought it was a religious shrine.

In Pearl Harbor, the USS Arizona and the remains of more than 1,000 sailors and Marines lie where the battleship sank on Dec. 7, 1941.

“;We're turning the page in both of these historic organizations,”; said Capt. Richard Kitchens, the Navy commander leading the joint base effort. “;We're joining them and changing their names. That's not something we should take lightly.”;