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

Home of the world's smallest dinosaur footprints.

A converted cattle farm is now a hub of art and theater surrounded by nature.

The colorful, smiling concrete silos of Vancouver.

This conservatory allows a little bit of the tropics to thrive in the middle of a major Canadian city.

This working class sculpture pounds his hammer all the livelong day.

A rotting tree in the middle of Seattle doubles as an elaborately-controlled art piece.

These locks on North America’s oldest canal are named after a porcine rock formation.

A sprawling Victorian farm that has been surrounded by a capital city is one of Canada's greatest treasures.

This inexpensive lodging house was once a prison notorious for its inhumane practices.

A Canadian POW for German soldiers during WWII where prisoners hatched an elaborate escape plan.

The oldest landmark of Toronto is a testament to shifting sands.

A school teacher's massive and terrifying self-built castle.

Louise Bourgeois' 30-foot-tall steel spider sculpture.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

Railroad came. People came. Railroad left. Town died.

An abandoned village that doubled as "The Hunger Games"' post-apocalyptic wasteland is up for grabs.

This wall on a street corner in Lower Manhattan has been a blank canvas for a rotation of renowned artists since the 1980s.

An artist's cute bronze subway sculptures belie his violent artistic past.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

One of only two commuter aerial tramways in the United States.