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

An innovative local park built from an abandoned sewage treatment plant.

The huge collection of paintings of the American West is one of Denver's best-kept secrets.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

This sidewalk tribute honors Colorado's great culinary creation.

A focal point of in Denver’s skyline for over a century, inspired by a Venetian basilica.

Inside houses a vast collection of military aircraft and missiles spanning the ages.

This midcentury chapel is a bold architectural statement and a symbol of Indiana's Lutheran heritage.

An 80-year-old plane tree is devouring an iron bench at Ireland's oldest law school.

The chaotic studio of one of the 20th century's most important artists has been preserved down to the dust.

A hidden piece of Altoona's railroad history in a long-forgotten abandoned town.

This piece of peacetime naval wreckage memorializes the tragic sinking of the USS Maine--an event which sparked the Spanish-American war.

Affectionately known as "Lord Bot," this historic statue has a cult social media following and rightly claims to be “the most metal inhabitant of the Wren Yard.”

Three and a half miles of cliffs, rocky beaches, Gilded Age mansions and 40 Steps to nowhere in particular.

A portion of the old Pirates stadium over which a defining home run once flew still stands even after the rest of the stadium was torn down.

Sections of the iconic limestone columns have been left uncleaned as a reminder of the city's polluted past.

A model of a dinosaur that was named for Andrew Carnegie stands outside the museum that also bears his name.

Once the most painted on object in the world, this short campus fence is well on its way to being so again.

Hundreds of protractors affixed to surfaces all over the city.

The last street in Pittsburgh that's paved with wood.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

Stolen goods adorn the organ at Old North Church.

An easy-to-miss garden in Boston's North End honors the mother of JFK and others who lost children in WWII.