On a cruise up the Ruhr in early adulthood, Mercer was impressed by the eclipse of artisanal culture by industrial production, and resolved himself to preserving artifacts of preindustrial life.

He believed that the story of human progress and accomplishments was told by the tools and objects that people used and saw these time-honored crafts slowly disappearing from memory.

In addition to tools, it displays furnishings of early America, carriages, stove plates, a gallows, antique fire engines, a whaleboat, and the Lenape Stone.

Mercer decided to build with concrete after the Great Boston Fire of 1872 destroyed his aunt's prized collection of medieval armor, which had been stored in wooden structures.

Locals mocked his choice of building materials, but on completion of the museum, he lit a bonfire on its roof to prove that it was fireproof.