A hollow cement depiction of time's inexorable effect on the human body.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

A subterranean house of worship carved right out of the bedrock.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

This sublime architectural marvel is a rare example of an expressionist church.

Pre-Nazi swastikas adorn the sculpted pachyderms flanking this brewhouse portal.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

Abandoned railway line circling the city of Paris.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

This historic covered bridge contains a series of macabre paintings that communicate one thing: everyone dies.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

One of the largest pieces of scientific equipment ever carried on a NASA space shuttle sits in a Chicago alley.