Which vegetable pie is traditional at southern Thanksgiving meals but less common elsewhere?

Sweet Potato pie

What Greek hero sailed to Troy and took ten years to return home to Ithaca? Who was the loyal wife who waited twenty years for Odysseus's return? What race is known as 'the fastest two minutes in sports'? Who performed the song "Happy" featured in the film "Despicable Me 2"? Which country has the largest land border with Russia?