In the middle of the 19th century, hundreds of thousands of new Americans flooded into New York. They found homes in buildings like this one, on Orchard Street on Manhattan’s Lower East Side, where the population density in some neighborhoods approached nearly a quarter-million people per square mile by the mid 1860s.

Architecturally, 97 Orchard St. was simple and indistinguishable from thousands of other utilitarian structures. Today, it is preserved by the Tenement Museum, an innovative public history organization. Inside, visitors can see relics and reminders of one of the most consequential migrations in human history, a flood tide of humanity that changed the fabric of America.