At the Lloyd Street Synagogue, just off Lombard Street’s Corned Beef Row, they’re scraping and digging and excavating deep into Baltimore City’s past. Down there, says Avi Decter. He points to a mikveh, the ritual bath for Jewish brides. It sits there, several feet below basement level and deep into the 19th century.

This is the oldest synagogue in Maryland, and the third-oldest still standing in America. It’s the first major congregation the Jews of Baltimore ever had, but it’s more than that. First it was a synagogue, later a church, then a synagogue again. Only in America. Now it’s a kind of museum.