A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

Famously misunderstood wonder of the ancient world

An opal mining town in the middle of Australia where people live, worship, and shop underground.

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

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

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

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

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

A former insane asylum despised by Nelly Bly and Charles Dickens is now fashionable apartments.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

A granite waterfall cascading down is one of the highest multi-tiered falls in the state.

A beautiful, but toxic, lake formed by mining.

Built over an abandoned train yard, this hidden gem is full of winding paths and offers gorgeous views of Sydney Harbour.

A New Zealand communications tower stands as the tallest structure in the Southern Hemisphere.

The real life Hobbiton, this sheep farm has been forever transformed since being built for The Hobbit film series.

This monumental Jesus is often referred to as "Our Milk Carton With Arms."

First planned industrial community in the United States.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.

A bronze statue dating back as far as 1252, still has remnants of gold on its right cheek from ancient gilding.

Nine Gardens in one—with tea service.

A collaboration of art and ornithology mourns the calls of Sydney's lost birds.

High winds can make this one scary landing.

New Zealand's only running funicular railway.

A galaxy of glowworms—larvae of a gnat—hides deep in the belly of these caves.