84-year-old Nat Read has seen it all - or at least everything you can see from an Amtrak train. Last month, Read completed his longtime goal of traveling every inch of Amtrak's 21,000-mile rail network. That includes trips to all seven continents and the North and South poles. He finished up his quest last month with a trip to Brunswick, Maine. Read told NPR "I see the railroad tracks across America as the lace that ties us together." What's the farthest you've ever traveled on a train?