1513 Turkish world map, full of European state secrets and snarky commentary.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

A marvel of Byzantine engineering under the streets of Istanbul.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

At 207 feet, one of the world's longest continuous escalators.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

The magic's in the hole!

This haunting tombstone comes complete with a heartbreaking story of love and loss.

Oldest existing church in New York and the inspiration for Washington Irving's "The Legend of Sleepy Hollow."

An 18th-century Spanish watchtower made entirely of seashell and concrete.

A lion given to the prime minister somehow got stuffed and sent to Florida.

Possibly the world's oldest rug, this Egyptian relic is woven entirely from ancient cat hair and once carried a mummified human foot.

Arrr! The most authentic collection of pirate artifacts in the world... matey.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A layered tribute to the work of mosaicist Isaiah Zagar.

The origin of this mechanical boy was a mystery until he revealed his maker by writing it in perfect cursive.

This elaborate towering structure was once famed for its revolutionary height.

Dr Barnes' $25 billion private collection of art and arboretum.

Yo, Adrian!

Eccentric concrete mansion and museum designed and built by hand from the inside out.

These 20-foot sculptures will help guide you from the local train station to the local sculpture garden.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.