Honolulu ? Most Americans have heard of the naval base at Pearl Harbor. Some are also aware of the air base next door called Hickam, where Japanese planes destroyed U.S. bombers during the 1941 aerial attack.

Today, the two historic 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. The large role the Japanese attack has in the national memory gives them an especially solemn responsibility to preserve and protect the historic sites within their grounds, military officials said.

“We are caretakers in this effort for the sake of all who came before us and actually died on our fields,” said Col. Giovanni Tuck, commander of the 15th Airlift Wing and the Air Force’s leader in the merger. “We just need to make sure we do this right by them.”

Pearl Harbor and Hickam have been close but distant neighbors for decades. They’re right next to one another on the southern edge of Oahu, but each have their own schools, golf courses, bowling alleys, churches and other facilities.

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 the fence in a symbolic ceremony.