As you drive Interstate 65 through cornfields 40 miles south of Indianapolis, the first sign you are coming to something special is the bright red twin arch over the freeway, known as Gateway Bridge.

And if you take the exit and follow Hwy. 46 east a few miles, you come to another sign: The bright red suspension bridge over the East Fork of the White River that frames a view of the Bartholomew County Courthouse and the tower of First Christian Church.

You are entering Columbus, Indiana. It's not what you'd expect of a Midwestern town of 39,000, built on a mix of agriculture and manufacturing. It is, in fact, one of the architectural gems of the nation. Yes, the nation.

Throughout the city are commercial buildings and churches by I.M. Pei, Eliel and Eero Saarinen, Cesar Pelli and other world-renowned architects. You'll find parks and gardens by landscape architect Dan Kiley, and public sculpture by Henry Moore. Altogether, internationally known architects designed more than 60 buildings.

Six of those 60 buildings have been designated national historic landmarks (even though only one meets the usual requirement of being at least 50 years old).

If you like civic architecture -- especially bold, clean modernism -- Columbus is worth a look. Pick up an architectural tour map and wander around town on your own. Or arrange, as I did, to take the two-hour tour, mostly by bus. The story of how Columbus became, in the words of Lady Bird Johnson, "the Athens of the prairie" is a testament to one man's power to shape a community. And the results are impressive to see.

The Saarinens design first

Founded in the early 1800s as the Bartholomew County seat on the confluence of several creeks, Columbus was pretty from its early days, boasting a fine courthouse built in 1874 and an 1895 Romanesque brick and stone city hall. But the architectural surge, with its modernist flavor, began in the 1930s, when the well-to-do congregation of First Christian Church set out to find an architect for a new sanctuary. After the Boston designer of a traditional Gothic church quit the project for medical reasons, the congregation recruited renowned Finnish architect Eliel Saarinen. When Saarinen declined the proposal, J. Irwin Miller, then the general manager of Cummins Engine, the major business in town, persuaded the architect to accept. According to family legend, Nettie Irwin Sweeney Miller, a member of the search committee and mother of Irwin, concluded, "Mr. Saarinen is probably going to build a building I won't like much personally, but it will be a great building."

Indeed it was. What Saarinen designed and the congregation completed in 1942 was perhaps the first modernist church in the United States, a masterpiece of clean lines and rectangular form, with a 166-foot-tall free-standing bell tower, and a large stone cross in the sanctuary's limestone facade. Saarinen defended his radical change in church design this way: "Our forefathers and we ourselves have been using the dead styles of alien cultures. We have combined them in thousands of different ways until the last drop of expressiveness has been squeezed out."

The next step in Columbus' architectural evolution came in 1954, with the construction of the Irwin Union Bank and Trust. Designed by Eero Saarinen, son of Eliel, the open glass pavilion broke all the rules for bank buildings -- few walls, few doors, few offices. As our volunteer tour guide Bob Bolner remarked as our air-conditioned bus glided through the downtown, "For the time it was not evolutionary; it was revolutionary."

Both First Christian and Irwin Union are national historic landmarks, and both were built with the involvement of the Irwin family -- old money in Columbus -- and specifically, of J. Irwin Miller. Miller, who returned from World War II to run Cummins Engine, even recruited Eero Saarinen to design his own home in 1957. Built in the International Style, it too became a national historic landmark.

School gets high marks

Miller, a fan of modernist architecture, sought to promote good architecture to arrest the deterioration of the core city as people moved to the outskirts. He also wanted to make the Columbus school system as attractive as possible to draw the kind of employees and residents he felt Columbus needed. So in 1954 he set up the Cummins Foundation to pay the fees of world-famous architects to design the city's schools. In 1957 the first project came of the Cummins-Columbus partnership: Chicago architect and Saarinen associate Harry Mohr Weese designed the Lillian Schmitt Elementary School with an open courtyard and ranch-style rooflines like those of the houses that surrounded it. (Eventually, Weese would design more buildings in Columbus than any other prominent architect.) Over the years, the foundation has paid out $15 million in architectural fees, not just for schools, but also for fire stations, public housing, hospitals and a jail--more than 40 projects in all.

The best place to start the tour of the buildings that Miller wrought is downtown, outside the Columbus Area Visitors Center. A few steps away you'll find the First Christian Church, a 20-foot-high bronze arch by English sculptor Henry Moore, and the public library, designed by I.M. Pei.

A couple blocks away is the Commons Center, designed by Cesar Pelli, and built in 1973 as one of the first enclosed urban malls. Inside is Chaos I, a kinetic sculpture by Jean Tinguely. Also housed in the Commons is the Columbus Gallery of the Indianapolis Museum of Art.

Keep on walking. Soon you'll come to the Irwin Union Bank, the Cummins Corporate Office Building (a precast concrete and glass building designed by Kevin Roche and built in 1983, with the Rudolph de Harak sculpture "Exploded Engine" in the lobby); the Columbus Post Office (the first post office designed by privately funded architects when it was built in 1970), and Mill Race Park (with an old-time covered bridge moved to the location, trails, amphitheater, ponds and public sculpture).

Design of churches soars

True to the origin of modern architecture in Columbus, some of the most memorable buildings in the city are its churches.