[todsul]

Just to follow up on laumac's comment, the booking instructions tend to be a large part of the secret sauce. In this case, we fully verified them and all the flights were bookable at the time of verification. We disallowed a few itineraries that didn't properly visit all continents. As an aside, it was interesting to define what countries fit in which continents. For example, Guam, Curacao, Turkey.

[prawn]

I think Istanbul is considered to straddle Europe and Asia.

Fly in to Ataturk (Istanbul), stay for a couple of nights, bus across the river and fly out of SGI (Istanbul). Europe and Asia, done?