Harry's Cafe de Wheels, Haymarket

Not the original at Woolloomooloo, and not on wheels any more, but a Sydney institution nevertheless.
Harry's started as a late night pie cart in 1938, a traditional stop for late night revellers finding their way home, taxi drivers and the like.
By the way, for North American readers, in Australia, "pie" is not synonymous with "sweet". They are most usually savoury, traditionally meat based, though being tri-lingual (we speak and understand Australian, English and American) there is some cross-over these days. My favourite are steak and kidney.