Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The FBI's urban training course may have the highest fake crime rate in the world.

At 207 feet, one of the world's longest continuous escalators.

A massive, abstract lookout tower providing a panoramic view of Prague.

Featuring the last fully walkable parapet walkway in Europe.

Thousands of tiny squares in different colors make up this piece of street art.

The sister plane of the C-123 shot down during the Iran-Contra Affair has found a new purpose in retirement.

This Dutch Colonial home is the oldest remaining farmhouse in Manhattan.

The last of nine massive kilns that produced many of the red bricks for buildings in Washington, D.C. and northern Virginia in the early 20th century.

Model Trains and Much More in Hamburg.

This "floating railway" is one of the world's oldest monorail systems.

Destructive children, start your engines.

Non-profit time travel mart sells goods you would need for a trip through the fourth dimension.

The oldest surviving presidential residence in the United States.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

World's first "penitentiary," meant to be humane, drove men insane.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

A student driver's nightmare.

Hidden beneath the streets of London is a secret subway that only carried mail.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A working miniature city designed to teach kids about safety and presumably city planning.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

Steepest flood safety railway in the entire world.