high heat ceramics for protective coatings.
pastries.
exporting their smartest to the USA. (there is a deep resentment there by that brain drain. those that stayed behind have this notion that those that prospered in the USA could have done their prospering in the current socialism of Greece.)
Marathon running industry. (can still run that marathon in marathon every year)
Olympic games. -pre doping
one of the hardest road rally races in world due to tough mountain roads
citizenship can be earned by more than mere birth.
beat back persians.
For the answer, see the chapter on Thermopylae and Salamis :)