Over a thousand feet beneath the Detroit streets is a subterranean metropolis few are allowed to enter.

One of Frank Lloyd Wright's greatest—and favorite—architectural masterpieces was almost lost.

This landmark jazz venue is the oldest continuously running African-American club in the United States.

A monument to a Polish general who fought the American Revolution and became the "Father of the American Cavalry."

A 19th-century architectural wonder designed by the "father of the skyscraper."

The absurd creation is a compulsory destination for selfies in Buffalo.

A monument honoring those who died in the Great Famine of Ireland.

This exhibit pays tribute to the “humble tinkerer” who invented the implantable pacemaker.

This small road tunnel is the only place where you can cross beneath the Erie Canal.

The "last holdout of the Confederacy” actually sat at the edge of the Canadian border.

A natural gas leak provides a flickering flame beneath a waterfall.

Buffalo's abandoned concrete grain elevators are getting a second life.

An elaborate memorial to a man local legend says died of a broken heart.

This sprawling collection of saintly relics includes such fascinations as wood from the Cross of Jesus and threads from Mary's veil.

A memorial to the tens of thousands of Irish who fled to North America during the Great Famine.

The Incredible Hulk, Yoda, Mulder and Scully, and many many others watch over the mean streets of Toronto.