The Massachusetts community where 20 people suspected of witchcraft were put to death in 1692 unveiled a memorial to 19 of those victims on Wednesday, promising never to forget the tragedy.

The ceremony came 325 years to the day when Sarah Good, Elizabeth Howe, Susannah Martin, Rebecca Nurse and Sarah Wildes were hanged at a site in Salem known as Proctor’s Ledge. It was the first of three mass hangings at the spot. The 20th victim was crushed to death.

“We should not be here commemorating the heartbreaking and tragic loss of life, it did not need to happen,” said the Rev. Jeff Barz-Snell, minister at the Unitarian Universalist First Church in Salem. “And so we are here to remember, to resolve, to rededicate.”