Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

A rotating cast of guys and dolls in front of a Washington, D.C. building.

This unacceptably tall building was the real reason for Washington, D.C.'s skyscraper ban.

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

This apartment building designed by a notable Washington D.C. architect housed the Qing Dynasty's Legation.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

This methodist cemetery is slowly receding into the wilderness along a Maryland highway.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.

More than 500 unique and specially designed cases collected by D.C.'s "Harmonica Case Man."

Obscure Freemasons still live in D.C.’s largest private residence.

Also known as the Founding Church of Scientology.

The only place for a truly presidential dram.

Surrounded by traditional homes, this Tolkien-esque dwelling stands out on a quiet street in suburban Maryland.

Built in the 1970s, this curious modular home found new life as a sundae-shaped ice cream stand.

The trials and tribulations of marking Poe's grave.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

World's first "penitentiary," meant to be humane, drove men insane.

The residents of this ominous-sounding street in Pennsylvania liked its name so much they fought to keep it.

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.

This twice-relocated "Usonian" home is among the smallest built by master architect Frank Lloyd Wright.

An astounding collection of medical specimens, including bits of President Lincoln.

The ruins of this Thomas-Jefferson-designed mansion have been left to crumble since the Christmas Day they burnt down.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.