If you stand outside the concentric rings of the University of Virginia’s new Memorial to Enslaved Laborers, there is a curious acoustic phenomenon: The conversations of people inside the gray, granite walls are clearly audible, even from a distance.

Architects Eric Howeler and Meejin Yoon say that’s no surprise, given the way curved surfaces reflect sound. “We knew the geometry had [acoustic] qualities, but it wasn’t until it was built that it became so evident,” says Yoon.

So, this evocative and moving new memorial to the thousands of enslaved people who helped build and then served the university that Thomas Jefferson designed can make private conversations public. And that echoes the larger challenge of this memorial, part of the university’s ongoing effort to confront the legacy of slavery and white supremacy: how to memorialize people whose names and stories are mostly lost to history.

Of the roughly 4,000 enslaved people whose lives intersected with the university — as construction workers, craftsmen, domestic servants, gardeners, cooks — the names of only 578 (to date) are known. Another 311 were known by their roles within the campus or their relation to others who lived or worked there: bricklayer, mother, son, niece.

That left more than 3,000 blank places on a wall meant to honor a whole community of people who were an essential part of university life but also subject to explosive violence and sexual abuse from students raised to be masters in a system of racial domination. The design solution is something the architects call “memory marks,” small gashes in the stone that stand in for the anonymous laborers, gashes that look a bit like wounds. After a rainstorm, a visitor to the memorial noticed that water was slowly dripping from the memory marks. That visitor, a descendant of the community of enslaved laborers, told the architects this reminded her of “the tears of our ancestors.”