An architectural oddity hides in plain sight on this iconic London bridge.

A sapling of the legendary tree where conquistador Hernán Cortés sat and wept after an Aztec uprising.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

Discarded animal sculptures stand forgotten by an abandoned aquarium and water park in Bosque de Chapultepec.

The gigantic skull of a long-extinct species that once roamed the forests of England and Ireland.

A gruesome and mysterious ancient sculpture of a pagan deity from the Roman occupation of Celtic Britain.

This magnificently macabre shield shows the power of chivalrous love in medieval times.

This intriguing Bronze Age artifact spent centuries hidden within a Welsh faerie hill.

This mundane post marks the old location of the city's main postal hub.

The Scottish Reformation leader's grave was paved over and is now a parking lot.

This museum houses two of Mexico's most impressive Aztec monoliths.

A striking depiction of Teotihuacan's mysterious "Spider Woman."

The largest outdoor art gallery in the Northwest United States.

Once home to an aristocratic family and a workers' organization, this intricately tiled building now houses a chain restaurant.

This 18th-century sundial was designed to calculate the date of Easter each year.

The ruins of the bathhouse used by the ill-fated last Aztec emperor still lie in Chapultepec Park.

This was once a hall in which a 16th-century royal banquet was hosted by King James VI of Scotland.

The final resting place of a German diplomat's beloved companion.

One of the figures in this Celtic sculpture continues to puzzle archaeologists.

This demon atop the Notre-Dame de Paris looks utterly bored.

Hollywood's oldest hotel is the site of the first Academy Awards, the birthplace of Marilyn Monroe's career, and the home of Montgomery Clift's ghost.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

This Viking gravestone carved in a rare runic style was dug up from a London churchyard.

It's a mystery why these remains were found with no traces of their bodies in sight.