Deceased nuns were placed on stone chairs to decompose, while the surviving nuns prayed near the lifeless bodies.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

The ritual has been performed uninterrupted for nearly 700 years.

Never actually a tree at all, this spot was the site of London's public hangings for nearly 600 years.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

A jungle cave in Peru of unknown depths, otherworldly sounds, and strange nocturnal birds that navigate by echolocation.

Colorful concentric circles honor a small Croatian town's supposed spot at the nucleus of it all.

One of only five observatories in the world built to measure the Earth's wobble.

A monument in the Belarusian city of Polotsk claims to mark the exact midpoint of the European continent.

An acoustic anomaly with a mysterious cause.

Many of Edinburgh's more unsavory characters spent their final days behind this door while awaiting their executions.

These paved rills bring freshwater into Altstadt and could spell wedding bells for whoever stumbles into the waters.

The ornate structure is part of a building boasting more marble than the Vatican.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

This influential Renaissance-era library was once the haunt of kings and monks.

This striking royal residence is the largest Renaissance-style castle in Scandinavia.

The first geometric self-supporting spiral stairs in Britain are a truly beautiful sight.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

For part of the year, this innovative greenhouse is painted white to keep the plants from getting scorched.

Oldest building in California still in use.

This hunter-gatherer architecture is believed to be the oldest religious complex known.

At an isolated roadside rest area stands a monument marking where famous Western star Tom Mix died in 1940.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

This oasis-like spring in the Sonoran Desert is home to unique, endangered species.