There are stories beneath our feet. Some are marvelous. Some are horrifying. Many are a mix of both. Here is what happens when we learn to unearth and examine them all. Walking the tree-lined streets of Bad Homburg, a suburb north of Frankfurt where my family and I have lived for many years, I sense daily the reverberations of stories beneath my feet. This happens in part by way of “Stolpersteine” (literally “stumbling stones”), the brass-covered, engraved blocks of cement cut the same size as surrounding cobblestones in between which these special markers are placed. Their location is significant: They point to the last residence of former locals who were…