At President Abraham Lincoln's funeral in 1865, the oak tree stood just a few feet from the event, shading the funeral choir.
More than 20 people have been killed in bombings or attacks in Pakistan in recent days.
One of those killed was a politician running for a provincial assembly seat in the May 11th elections.
The landmark polls will see power pass from a civilian government that completed its full term to another elected government. But secular anti-Taliban parties have had to curtail their campaigns because of threats from militants.
After five years of democratic rule, Pakistan is struggling with terrorist attacks, inflation and crippling power cuts.
The party led by the former cricket captain, Imran Khan, has been gaining ground and could change the political landscape.
The BBC’s Orla Guerin joined him on the campaign trail in Punjab.
Peter O’Dowd follows the route of Abraham Lincoln's funeral train 150 years ago, to look at modern-day race relations and Lincoln's legacy.