David Starkey starts this 59 minute documentary near Runnymede (just outside of London on the Thames), where the "Great Charter" was first agreed in 1215. Near the latter part of this engaging documentary Starkey walks through the Pennsylvania State House in Philadelphia ("America's Runnymede," in Starkey's characterization), where America's Constitution was written.
In between he addresses King John, the English Civil War, the execution of Charles I outside the Banqueting House in Whitehall... as Starkey stands across the street from such looking at the window through which Charles walked onto the platform raised above the street level with the window through which Charles had come.
Starkey also walks along the beach in Virginia where English colonists arrived from English, through the US Capitol, to the outside door of America's Supreme Court building (on which a panel depicting King John is displayed). All the while Starkey highlights the points of Magna Carta and the notion that power corrupts and that people's liberties are continually at risk, especially when people get lazy about holding their governments to account.