As a stopover point from the US to Greece???
If the OP is going through ORD anyway (from Des Moines), there's a nonstop on Turkish, and then just a short hop to ATH vs. somewhere like London or Amsterdam, so it's not as crazy as it sounds. And actually TK offers free city tours which the OP could take advantage of on a long layover, if desired.
But it did seem in the initial post that the OP was looking to have two shorter flights to get out and stretch a little rather than one even longer flight.