It’s an iconic photo: eleven men sit on a steel beam high above Manhattan, relaxed and enjoying a meal in the most unlikely of settings.

If you’ve seen the picture, you may have wondered about the lives of the men it captures, perhaps even admired the nonchalance with which they sit perched at a heart-stopping height in the middle of the construction of the illustrious Rockefeller Center in 1932.

If you have, you’re not the only one – and this September, PBS America has the answers.

In documentary Men at Lunch, director Seán Ó Cualáin uses ‘Lunch Atop a Skyscraper’ as a stepping point from which to take an earnest look at the reality of life for Irish immigrants in Manhattan during the Depression. Though integral to the construction of the city’s famous skyline, very little information is known about the workers in the photo and the thousands like them who lived and worked during this formative era in New York’s history.

The documentary uses archival footage and photographs, along with first-person interviews with experts, relatives and photographers, to uncover the story of the men behind the photo.

Men at Lunch is narrated by Fionnula Flanagan (Lost, The Others) and premieres on PBS America Friday 7 September at 9pm. PBS America is available on Freeview 94, Freesat 155, Virgin Media 276 and Sky 160.