Story highlights Greg Zanis says he's hand-delivered more than 20,000 crosses in 20 years

He recently has crisscrossed the nation to respond to deadly attacks

(CNN) For Greg Zanis, mourning is a full-time job

In just the past few weeks,he's been to Las Vegas, where 58 people were killed in the deadliest mass shooting in modern US history. And to New York City, where eight people were killed in a terror attack on a Manhattan bike path. And to Sutherland Springs, Texas, where 25 people and an unborn child were gunned down in a church sanctuary.

"For a month and a half now, I've been doing nothing but making full-time crosses," he says.

For Zanis, 66, the stopovers represent wayposts on a seemingly endless effort to share in -- and, hopefully, to ease -- the personal grief that lies beneath some of the most horrific headlines for our time. A retired carpenter, he fulfills his mission methodically, memorializing with handmade wooden crosses the victims of mass shootings and other national tragedies at or near the places where their blood was shed.

Zanis crisscrosses the country in a pickup truck filled with his handiwork. And he's never in one place for long. Tragedy, it seems, is always lying in wait, ready to bring the country to its knees -- again.

Greg Zanis readies his truck with crosses for the shooting victims in Sutherland Springs, Texas.

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