A Century of Progress International Exposition was a World's Fair registered under the Bureau International des Expositions (BIE), which was held in Chicago, as The Chicago World's Fair, from 1933 to 1934 to celebrate the city's centennial.
At the Chicago World's Fair 1933-34, the visitors entering by the North
Entrance, next to the Shedd Aquarium, would see before them the Avenue of Flags,
stretching North - South, from the Field Museum, past Soldier Field, all the way
to the Hall of Science, with its Carillon Tower. For the duration of the fair
this wasn't the Leif Ericson Drive as it was normally named in
those days, but rather it was named for the huge flags that lined it on both
sides high above the visitors' heads. The flies of the flag may well have
been 10 metres above the ground, the trucks could well be 25 metres above it.
There are different views on what the flags looked like, apart from "huge".
Regularly, Ebay offers images of the Chicago World's Fair's Avenue of Flags
for sale. For example:
https://www.ebay.com/itm/123552603585 - The 1933
Official View book: Here, the flags are shown as cut to hang straight from an
angled staff, with long rectangular splits in them (closed of at the ends),
making them partly see-through. Though these gaps remind me of the jags in
historical clothing, they seem(ed) to give an impression of "future". This
would match the Fair's "A century of progress". As the bus-like car in the
picture seems future-vision as well, I would say this image is rather an
impression of what the Avenue of Flags was going to look like. (After all, to
have an official 1933 view book ready by the time the Fair starts, your
artwork will have to be made beforehand.)
The top one shows the flags is different colours, but the photograph has been
coloured in. (At the New York World's Fair 1964-65, such coloured flags were
indeed used, though.) We see lighter edges, but it's unclear whether these
are for real.
The other two are interesting as they both are realistic
photographs. Note that the first has the flags much darker than the second. I
doubt that is caused by the first being southward and the second being northward. The darker, southward ones really do seem to have a lighter edge.
The last one is a drawing of the flags being red with a yellow lower flyward edge.
Turning to the Internet once more, I find that looking
for images explicitly related to 1933, will give results with these red with
yellow flags. Doing the same for 1934, will give you a few hits for green flags:
The 1933 flags on the Avenue of Flags have probably been red
with a yellow edge. The 1934 flags were probably not really white, but rather had a colour that showed white. I imagine both the shades of green and those
of blue would do so, though I have a slight preference for the blue in this
case. Peter Hans van den Muijzenberg, 3 April 2019