A wall of chewing gum moonlights as collective art.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

Half-sized replica of the Leaning Tower of Pisa built to honor Galileo.

A science teacher's dream.

A restored Pittsburgh house of God has been converted to a marvelous house of suds.

Meet your friends, marry your true love, or tell your enemies to kiss your butt under this historic Pittsburgh timepiece.

There aren't too many operational funiculars around, but Pittsburgh has two!

Famous church recognized for both its unique design and disciplined monks that live according to the Benedictine discipline.

Less a museum than a bizarre fantasy world created by artists and engineers.

Ancient pueblos built into the base of a natural canyon wall.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Home with Gothic windows featured in a famous painting.

Another in a long tradition of legends regarding infernal seats.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.