This tower was once used to create ammunition for early settlers.

The lesser-known Alice sculpture of Central Park dedicated to the “godmother of American children.”

The "World's Largest Underground Business Complex," a 55,000,000-square-foot city underneath Missouri.

A magnificent church designed by world-renowned architect, Frank Lloyd Wright.

A piece of John the Baptist in the American heartland.

Four, 18-foot-tall badminton shuttlecocks lie scattered about the lawn of a Kansas City museum.

This otherworldly church spire reaches up toward the heavens.

A remarkably opulent mansion with a tragic history.

An abandoned concrete jungle surrounded by a lush park.

Two hundred tons of pioneer artifacts were painstakingly recovered from a shipwreck at the bottom of the Missouri River.

This Italianate Villa-style castle is pretty to look at, just keep off the private property.

This sacred space and gathering spot for the Wyandot Nation has been the surrounded by controversy and confusion.

Why settle for barbecue chips when you can get actual barbecue?

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

This clifftop arch is a natural stunner.

Breathtaking and huge 430 year old maps of Italy.

This equestrian statue of Constantine the Great has been the subject of criticism for centuries.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

These spartan apartments are provided to clergymen visiting Vatican City.

Ancient ruins hidden underneath a modern luxury hotel.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.