At just 25 inches at its narrowest point, it's one of the tightest streets in the world.

There must be a pun in this haystack somewhere...

This Fifth Avenue church has long been the favored worshiping place of Broadway actors and vaudeville performers.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

A 19th-century politician who died after walking home in a blizzard is honored with this Manhattan statue.

A good place to research the Freemasons, esoterica, occultism, and hermeticism.

The original toys that inspired the beloved children's stories are on display at the New York Public Library.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A very classy 1920s-era bar right in Grand Central Station.

This subterranean oyster house has been the pearl of Grand Central Station since 1913.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Turntable anonymously received orphans, alms, and groceries.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

One of Antoni Gaudí’s earliest buildings, built between 1886 and 1890 for the industrialist Eusebi Güell.

The pretty iron lamp is a reminder of the architecture underneath London's streets.

The broken skateboards that became a poignant memorial to a murdered skater.

London's smallest police station is barely the size of a phone booth.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

London's old-school healing garden.