It looks like the final memory challenge has the "Hello" and "Goodbye" we expected. They have to raise banners with the correct "Hello" and "Goodbye" to match the country's flag flying at the top.
There is a US flag that may already have the banners in place as an example.
There is also a Mexican flag in the shot so that means that there are phony route countries in place to foil the Racers.
The location appears to match this Google Streetview: Link
Everyone knows this location as the United Nations Building
in New York City. Note the flags reflecting in the windows at the bottom of the Streetview image.