The largest flower auction house in the world.

A Dutch clog company in the town of Zaandam loves the wooden shoes so much it made a museum for them.

Colorful and chaotic stacked hotel in North Holland.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

A unique collection of gilded age mechanical pianos.

A rare tour of an aristocrat's private home reveals valuable 17th-century paintings from artists like Rembrandt.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

A collection of biblical memorabilia.

Amsterdam's former hotspot for public executions and dissections.

A beautifully eclectic mix of architectural styles.

The history and future of cannabis.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

The U.S. Fish Commission’s effort to mass produce carp.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

The shelves in the back of this thrift store are devoted to saving, not selling, retro tech.

A pre-Industrial Age iron furnace and the site of a nearly-forgotten piece of Black history.

The whole world in one water tank.

This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

Bizarre Cavern.

A monument marks the location of the first successful steamboat demonstration.

Conveniently located within binocular range of a nuclear bunker, the "summer camp" area was a painfully obvious spy house.

The Grand Ole Opry's big voice came from a small home in rural Virginia where she was eventually buried.