91福利社

It is the most bitterly fought US election in living memory, and it is going right down to the wire.

The fight is toughest in the so-called battleground states, especially those with large numbers of votes in the electoral college.

Pennsylvania is being bombarded by politicians. Traditionally Democrat, it's called Clinton's political firewall, but are there cracks appearing?

Martha Kearney returns to Pittsburgh where her family lived when her father taught at the university.

(Photo: The Duquesne Incline in Pittsburgh. Credit: Getty Images)