Interest in Chicago architects increased after the 2004 publication of Erik Larson's "Devil in the White City," a story of Chicago's 1893 World's Fair that tells of architect Daniel Burnham and serial killer H.H. Holmes. Along with Burnham, Stanford says interest piqued in Chicago architects Frank Lloyd Wright and his Prairie Style, Louis Sullivan and his ornate facades, and Ludwig Mies van der Rohe, known for a sleek, modern design.

"People like to see something by these people," Stanford says. He gets questions about what the architects were like as people during his tours, he adds. "It sort of connects them to them. They were all great characters."

More than a century later, Chicago architecture continues to welcome groundbreaking designs, said Mark Sexton, whose Chicago firm Krueck and Sexton designed Millenium Park's Crown Fountain and the Spertus Institute of Jewish Studies.

He says today's architects look to the city's historic buildings to inspire the future.

"Here's a great opportunity not to be timid," Sexton said. "Because Burnham and Sullivan and Wright were not timid. They were pushing the limits of technology and thinking. We thought we should do the same thing."

He said Chicago is special because classic and modern buildings complement each other.

"The two can coexist, each one making the other better," he said. "That's what architecture leaves. It leaves an indelible print."

If you go ...

BOAT: Chicago River cruises take tourists on open-air boats with enclosed lower decks and sometimes, bars. Cruises sail by Chicago standbys, the Merchandise Mart, Tribune Tower, Sears Tower and the corn cob Marina Towers, led by knowledgeable docents.

— Chicago Architecture Foundation: Several boats daily on the hour, May 4-Nov. 23; $28 during the week, $30 Saturday, Sunday, holidays.

— Shoreline Sightseeing: Boats daily, April 1-Nov. 30. Adults, $24 weekdays, $26 weekends; seniors, $21 weekdays, $23 weekends; children, $12 weekdays, $13 weekends.

— Wendella: Six boats daily. Adults $22; age 65 and over, $20; age 11 and under, $11; under age 3, no charge.

BICYCLE: The Architecture Foundation offers three-hour bicycle tours from Millennium Park along Lake Michigan , and covers the museum campus, Soldier Field and Northerly Island . Bring your own bike or rent one. Adults, $10; students and seniors, $5.

BUS: The Architecture Foundation offers a dozen different bus tours covering the city. The most popular is Highlights by Bus takings tourists 30 miles through the Loop, Hyde Park and Gold Coast. Daily tours, adults, $40; seniors and students, $35.

ON FOOT: The Chicago Architecture Foundation offers more than 60 different walking tours of the city's buildings , featuring tours by specific architect, neighborhood, cemetery, street or skyscraper . Tours priced $20-$5.

ASSORTED: The foundation also offers happy hour tours, lunchtime lectures and tours in foreign languages. It also has a museum with permanent and rotating exhibitions and a lecture hall. Details from Chicago Architecture Foundation, 224 S. Michigan Ave., Chicago; www.architecture.org or 312-922-3432; open daily 9 a.m.-5 p.m.