Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

A Victorian cemetery in the heart of Brooklyn remains a popular mecca of morbid curiosity.

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

A quiet and contemplative oasis in the middle of New York's bustle and riot.

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

The only home that Alexander Hamilton ever owned has a history almost as troubled as his own.

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

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

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

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

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

One of only two commuter aerial tramways in the United States.

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

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

A crumbling hospital from the 1850s on Roosevelt Island.

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

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

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.

This cafe offers a curated collection of treats and tipples made by monks and nuns.

The unexpectedly beloved remnants of a controversial thermal power plant.

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

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

A statue commemorating a beloved stray dog who was adopted by the entire neighborhood where he lived.

A lush indoor jungle fills this bustling Madrid transportation hub.