The Wright-Patterson Air Force Base, in Dayton, Ohio, is so sprawling, it has its own ZIP code. But in the early 1900s, it was the prairie where the Wright brothers used to test their invention, the airplane.

There's no bigger monument to the Wrights than the National Museum of the United States Air Force.

The Air Force museum is open 9 a.m. to 5 p.m. every day but three (Thanksgiving, Christmas Day and New Year's Day). And it's free.

That last part is amazing when you see how much you get at what is billed as "the world's largest and oldest military aviation museum."

Most of the exhibits are inside three interconnected aircraft hangars. More varied aircraft than most people can imagine are hanging and otherwise artfully arranged inside the cavernous spaces, dramatically spotlit and decorated with realistic mannequins and other props.

As my first-grader put it, "The fake people are kind of freaky. They look right at you!"

The individual planes are mapped on the foldout "aircraft locator" that we received upon entering and that showed how they are grouped by eras. Rather than start with the Wrights in the "Early Years" exhibit, we were drawn into the "World War II" gallery, so thick with history that it really felt a little like traveling back in time. The airplanes and the context are illuminated by videos, soundtracks and related artifacts.

I found myself learning about lesser-known things, such as "The Hump" that Allied pilots had to fly over from India to China. And I found myself moved to see better-known things, such as "The Aircraft that Ended WWII" — the "Bockscar" B-29 Superfortress that dropped the Fat Man atomic bomb on Nagasaki.

We finally made it out of that first exhibit and into the one next door, where we saw a reproduction Wilbur Wright on a reproduction Wright 1909 Military Flyer, which the Army bought as the first heavier-than-air military flying machine.

The exhibits that follow dramatically tell the story about all that happened next, as the Army begot the Air Force and it flew into the "Korean War," the "Southeast Asia War" and then the "Cold War." Depending on your age and background, different planes and pieces will stand out, each having starred in some aspect of history, from the Berlin airlift to the Vietnam War to the moon landing.

In an adjacent silo, I was reminded that there still are LGM-30 Minuteman intercontinental ballistic missiles "on alert." Before we left, we quickly explored the outdoor "Air Park," which has more planes as well as buildings, including a reconstructed Nissen hut that used to house U.S. airmen near London. I loved looking around the reconstructed Belly Tank Bar, complete with British beer engines, where the mannequins' American voices bellyached about British ales: "Don't look for any cold ones. They're all going to be warm."

There is much more to see than we could in three hours. With more time, we could have signed up for the bus trip to see the "Presidential Aircraft" and "Research & Development" exhibits, both of which sound excellent. We somehow missed the new space shuttle crew compartment trainer exhibit. The museum didn't get one of the actual shuttles that NASA retired, but it did get this trainer, in which scores of astronauts trained over three decades. That exhibit opened in the Cold War gallery this spring.

Much more is in the works. Earlier this month, the museum broke ground on a $35.4 million fourth main building, which is to house the presidential and experimental stuff and more; it will open in 2016. It will expand the existing 1 million square feet of exhibit space by nearly a quarter million square feet of more good stuff.

Whenever you go, and I strongly recommend that you do, I think you'll be struck by how much the U.S. Air Force, how much military aircraft, and how much Wilbur Wright, have affected the past century of history.

More info: 1-937-255-3286; www.nationalmuseum.af.mil