What to Watch on Monday: ‘Mystery at Jamestown’ and more ‘Bachelorette’ drama

America’s Hidden Stories: Mystery at Jamestown (8 p.m., Smithsonian Channel) - The Smithsonian Channel marks the 400th anniversary of the first American Democratic Assembly with the search for lost founding father, Sir George Yeardley. Yeardley presided over the first democratic assembly in English-speaking America in 1619, and just a few weeks later purchased the first captive Africans for an English colony, opening America to the horrors of slavery. This special “Jamestown” episode reveals how in a single year Yeardley set the course for the nation’s future.

The Bachelorette: Finale, Part 1 (8 p.m., ABC) - Yes, Part 1. They’re dragging this out over two nights. Tonight Hannah will continue to feel torn over which of the three remaining men she will choose, and she talks to host Chris Harrison about her experience. Tomorrow night is the true finale.

Serial Killer: Devil Unchained (9 p.m., Investigation Discovery) - Parts 3 and 4 of ID’s documentary series on South Carolina serial killer Todd Kohlhepp. Tonight, Maria Awes visits the scene of the Superbike murders with the man who discovered the bodies moments after the crime.

Inventing Tomorrow (10 p.m., PBS / UNC-TV) - This POV documentary looks at six young scientists from Hawaii, Indonesia, India and Mexico as they tackle some of the most complex environmental issues facing humanity today. This film, directed by Laura Nix, won the Grand Jury Prize for Best Documentary Feature at the Seattle International Film Festival.

Some programming descriptions are provided by networks.