Cities rarely ask the child's eternal question, "Where did I come from?" but Dublin filmmakers Bonnie Dempsey and David O'Sullivan have given it serious thought. Their documentary project, We Built This City, examines the role Irish labour played in creating London, Chicago, and New York, a story rarely acknowledged in standard histories.

The Irish Architecture Foundation commissioned Dempsey and O'Sullivan to produce three films as part of Irish Design 2015 (ID2015), an initiative backed by the Irish Government that celebrates and promotes Irish design in Ireland and internationally. This collaboration with the Office of the Minister for Diaspora Affairs also includes an exhibit curated by Nathalie Weadick and Raymund Ryan at the Chicago Design Museum, highlighting the work of contemporary Irish designers.

Whereas the memory of Irish labour rebuilding metropolitan London after the second World War has not faded from public consciousness, in Chicago, the filmmakers discovered that the city's Irish roots were practically unknown. Their documentary opens in Chicago's Millennium Park, the city's most popular public space (home to Anish Kapoor's iconic Cloud Gate/ "the Bean"), with residents and visitors alike shaking their heads when asked about the city's origins.

When an African-American woman finally reaches for her phone and asks Siri, “Who built Chicago?”, laughter spread throughout the sold-out crowd who gathered for the screening earlier this month at the city’s prestigious Arts Club on Ontario Street, just off Chicago’s “Magnificent Mile”.

Chicagoans are understandably proud that their city was the birthplace of the skyscraper in the 19th century, but few know that in the 1830s, Irish immigrants dug the Illinois & Michigan Canal that assured the growth of the frontier town on the shores of Lake Michigan.

Clare Lyster, an Irish-trained architect who now teaches at the University of Illinois at Chicago’s School of Architecture, does more than narrate the film. She registers her own growing sense of awareness of the complex role the Irish have played in shaping the city physically, culturally, and politically, all the more intriguing because they never formed more than 20 per cent of Chicago’s population.

We Built This City juxtaposes dramatic views of Chicago’s lakefront and vibrant downtown with the modest neighborhood homes built by canal workers. The film also captures the beauty of Old St Patrick’s, the “mother parish” of the Chicago Irish. Now the oldest public building in Chicago, the brick church dedicated in 1856 reflected the outsize ambitions of Irish immigrants to put their imprint on the urban landscape. Men and women, many refugees of the Great Famine in Ireland, contributed scarce nickels and dimes to build the first Romanesque house of worship in the city that invited favorable comparisons with the Smithsonian Institution in Washington, D.C.

As Clare and I sat in the curvilinear pews of St Patrick’s, surrounded by Thomas O’Shaughnessy’s marvelous Celtic stencils and stained glass windows, we talked about the ways in which Irish women built the city through their schools and hospitals and charitable institutions.

Only later did I realise we had neglected to discuss Catherine O’Leary, an Irish immigrant unfairly blamed for starting the Great Chicago Fire of 1871. Her cow allegedly knocked over a lantern in the family’s barn and the flames spread across the river, destroying the city’s business district and lakefront homes. Shamed and shunned, Mrs O’Leary refused to give interviews or cash in on her notoriety.

But when she died in 1895, a prominent architectural journal came close to calling Mrs O’Leary the patron saint of Chicago architecture, characterising the Great Fire as “a blessing in disguise” that cleared the way for “the brightest flowers of architecture”.

While architects of Irish birth and descent, including James J Egan, Louis H Sullivan, Barry Byrne, Marion Mahony, and Joseph W McCarthy contributed to Chicago’s reputation for innovative design, since the 1940s, designers from Ireland have been profoundly influenced by the modern style of Ludwig Mies van der Rohe’s “Second Chicago School”.

Through stunning images and narration, We Built this City explores what Nathalie Weadick has called a “hidden story of the Irish diaspora”, the role immigrant men and women have played in shaping urban life globally.

The conversation continues as Dyehouse Films directors Bonnie Dempsey and David O'Sullivan focus their cameras on New York in the spring of 2016. See architecturefoundation.ie.

Ellen Skerrett is an historian of Chicago and its neighborhoods with a special interest in Irish America. ellenskerrett.com