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

You can spend the night as an honorary lighthouse keeper in this quaint, historic beacon.

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

Books bound in human skin and H. P. Lovecraft's letters are among a few of the treasures this library has to offer.

A 19th century library favored by Edgar Allan Poe and H.P. Lovecraft, known by locals as "the Ath."

Baroque celebration of the end of the Great Plague of Vienna.

The beautiful baroque library of the Hapsburg empire.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

This World War II bunker now survives as a documentation of the Nazi regime and war crimes.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

Tiny memorials honor individual victims of the Holocaust.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

There has been an astronomical clock on this spot since the 14th century.

Visitors dating back to the 1600s carved their marks in the stones of the iconic tower.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

A geothermal energy project gone wrong is fracturing the city's picturesque architecture.

A stonemason's hilarious revenge came in the form of this peculiarly positioned gargoyle.

This medieval cathedral houses stained-glass windows featuring saints and pretzels.

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

This Late Gothic building that once housed Erasmus is now known as the filming location of "Suspiria."

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

Home to items never before seen by the public.