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

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

Elevated freight railway turned wildly successful urban park.

This elaborate towering structure was once famed for its revolutionary height.

Yo, Adrian!

World's first "penitentiary," meant to be humane, drove men insane.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

This monument on Breed's Hill proves that one of the most famous battles of the Revolutionary War is misnamed.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

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

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

Berlin's beloved bear is immortalized at the Museum für Naturkunde.

A brush maker used his factory to protect blind Jews from the Gestapo.

A restaurant and observation deck built in a unique broadcasting antenna.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The most visited, and possibly most controversial, museum in Germany.

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

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.

Relive a Polish uprising via an enormous, century-old cyclorama.

While the U.S. and Soviet Union were engaged in a space race, Poland built a UFO on the ground.

Deep in a Polish forest, this collection of Iron Age megaliths still holds onto many of its ancient secrets.

A striking public sculpture representing the period of martial law in Communist Poland.