The RIAI's Chicago conference was as much a pilgrimage as anything else, as Irish architects availed of tours to see and experience some of the icons of 20th century architecture by two of its great masters, Ludwig Mies van der Rohe and Frank Lloyd Wright.
For it was in the Windy City that they left the largest concentrations of their work, Wright in the leafy suburb of Oak Park - described by Hemingway, who grew up there, as having "wide lawns and narrow minds" - and Mies at the Illinois Institute of Technology (IIT).
Wright is a popular favourite in the US and his "prairie-style" houses are looked after by foundations or by private owners. There would be no question nowadays of any of his buildings being demolished, a threat that once hung over even his outstanding Robie House.
Visitors are escorted around in an atmosphere of hushed reverential awe, with the guides irritatingly referring to him as "Mr Wright" even though he has been dead for many years. Nobody is allowed to take photographs or even to touch the wood-panelled walls.
A total of 27 Wright houses survive in Oak Park, many of them within two blocks of his own home and studio, a showpiece for his design flair and ingenuity. It was here that he developed the Prairie style, with its horizontal lines, continuous windows and overhanging eaves.
Wright's most radical building in Oak Park is not a house, but a church - the Unity Temple, a massive cubic structure with tall, solid concrete walls. Different writers over the years suggested that it looked more like a prison, an ice-making plant or a Mayan handball court.
Despite being one of Wright's greatest works and its designation as a national historic landmark, the Unitarian congregation is left to beg funds from private foundations to finance a $2 million restoration programme; no federal government money is available.
The same is true of IIT, where a staggering $100 million is needed to restore Mies's buildings - including Crown Hall, the institute's school of architecture. Though all less than 50 years old, these classics of modern architecture are in a state of serious decay.
To see the rusting exteriors and run-down interiors - the suspended ceiling over the "universal space" of Crown Hall is like a patchwork quilt of polystyrene - was quite a shock. (In the basement, all the models produced by IIT's architecture students were skyscrapers).
At least Mies's Farnsworth House is in the hands of a caring owner, Lord Palumbo, who is a collector of architecture. Built in a bucolic setting near Plano, 60 miles southwest of Chicago, it was designed as a weekend retreat for Dr Edith Farnsworth, a prominent physician.
The good doctor fell out with Mies over the soaring budget for this ultimate expression of his "Less is more" philosophy; the house, made of white-painted steel and plate glass, had cost $74,000 (about $0.5 million in today's money) by the time it was completed in 1951.
It was an ill-fated project. Two years later, the Fox River burst its banks and flooded the house, destroying the silk curtains and damaging the expensive Privavera panelling on its service core. A road built just 100 metres away in the mid-1950s ruined its tranquil setting.
This serene house, a true icon of modern architecture, was flooded again two years ago and its panelling had to be replaced for a second time. With the onset of climate change, such disasters will become more frequent, rendering it unsustainable without radical measures.
Back in Chicago, it was also fascinating to see the Church of St Thomas the Apostle, dating from 1924 and billed as the first modern Catholic church in the US. Its young architect, Barry Byrne, went on to design Ireland's first modern church, Christ the King in Turner's Cross, Cork.
