The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

Commonly acknowledged as the only public monument to the Devil himself.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

An ancient Egyptian temple in the middle of Madrid, Spain.

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

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

A lush indoor jungle fills this bustling Madrid transportation hub.

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

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

The most confusing clock in New York.

Commemorating the spot where the famous scientist fed his pigeons.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

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

Visit the monolithic tomb of America's most famous general.

Love, knishes, and best wishes from this legendary Lower East Side bakery.

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

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

A popular European tradition makes its way to the states on one of America's most famous bridges.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

Mysterious 500-year-old tapestries depict a unicorn hunt.

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

Elevated freight railway turned wildly successful urban park.

This city park was once a lookout point for George Washington’s army during the Battle of Brooklyn in 1776.