The perfectly preserved underground rooms where Churchill plotted the war against Germany.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Sit where JFK proposed to Jackie or where Nixon dined on meatloaf at this storied pub.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

The privately owned cemetery that holds room for Washington's finest when they step down from life.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

When it opened during the final years of the embargo, all the drinks and cigars were free.

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

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.