This work of art was designed to represent the Tarpeian Way Quarry that once dominated the area.

The highest concentration of Art Deco buildings in the world.

The platform atop this verdant volcano was built with the help of a royal elephant.

Twelve decommissioned shipping containers evoke a reclining person in Marfa, Texas.

Astonishing collection of helmets, scientific instruments, and medical models.

This saltwater swimming pool, which is the last of its kind in the United States, is slowly crumbling within sight of multiple high-end beachside hotels.

On Waikīkī Beach, a monument to four extraordinary individuals of dual male and female spirits who brought the healing arts from Tahiti to Hawai'i.

Hiding in plane sight.

A unique set of caves that spits waves back out into the ocean.

Along a California highway is a kind of Jurassic Park made of metal.

Version of the French Riviera destroyed by the sea.

This popular park is home to a sea serpent sculpture that now overshadows the twisted history of its creation.

The symbol was surreptitiously built into the river bank by German prisoners of war.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

The big toe of this towering monument to a Croatian national hero is worn from years of superstitious rubbing.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

This seven-sided Romanesque chapel is regarded as the oldest building in Rovinj.

A recreated Stonehenge stands in a country field, complete with Easter Island moai heads standing as sentries.

Three and a half miles of cliffs, rocky beaches, Gilded Age mansions and 40 Steps to nowhere in particular.

Mysterious stone tower featured in many alternative histories of the New World.

A promotional sun clock on the site of San Francisco's great raceway.