Walking down the cobblestone streets of Salem, Mass., I was both intrigued and a bit spooked. In every other window, witch paraphernalia was displayed – ouija boards, spell candles, black cats. The Salem Witch Museum is in an old church with the glass windows lit in red. It is dusk and the perfect setting for my visit. Turning a corner, we walked by a historic home, graveyard and a group of tourists being led by a man dressed vaguely as a pilgrim. My friend tells me to look down. I see a row of stones, engraved with words in capital letters. Some of the stones are cracked. Yellow leaves obscure parts of the text. But I see phrases: “I am innocent” . . . She tells me these are the last words of the men and women hanged after being accused of witchcraft. It takes my breath away. When I look up, I notice a small courtyard – again surrounded by a stone wall. There are small stone platforms jutting out of the wall – about 20 of them – encircling the courtyard. I thought the...