The ornate structure is part of a building boasting more marble than the Vatican.

Glasgow’s piece of the patron saint of love.

A scattered trail of street art adds a pop of color to the city's stark structures.

A sculpture of a salmon swimming through a brick building.

The magic's in the hole!

Tens of thousands of tiny birds swarm into one school chimney every fall.

The world's smallest park was dedicated in 1948 as the only colony for leprechauns west of Ireland.

World's only nuclear reactor operated by liberal arts undergraduates.

Walk in the footsteps of the gods and straddle two tectonic plates.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

This colorful statue welcomes visitors to a Barcelona park.

This 700-year-old street food market features baby octopus and soy donuts.

Tiki luxury on Nob Hill.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

The massive machine creates cracking displays of indoor lightning.

Located in Faneuil Hall, the headquarters of the Ancient and Honorable Artillery Company of Massachusetts has stood the test of time.

American revolutionaries and British soldiers alike are buried here in the fourth-ever cemetery in Boston.

The Boston square dedicated to the dark poet who was born nearby.

The former locus of Boston's high culture has been shuttered and buried for over 70 years.

The oldest working bell set in North America, the bells at Old North Church sat silent for their first four years in Massachusetts.

This bright yellow relic is the final survivor of a short burst of seashell-shaped petrol pumps.

The red brick house where the father of rock 'n' roll wrote some of his classic hits.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.