London (Greenwich)

About 8 miles downstream—which means seaward, to the east—from central London, Greenwich is a small borough that looms large across the world. Once the seat of British naval power, it is not only home to the Old Royal Observatory, which measures time for our entire planet, but also the Greenwich Meridian, which divides the world into two—you can stand astride it with one foot in either hemisphere. Bear in mind that the journey to Greenwich is an event in itself. In a rush, you can take the driverless DLR train—but many opt for arriving by boat along the Thames.

This way, you glide past famous sights on the London skyline (there’s a guaranteed spine chill on passing the Tower) and ever-changing docklands, and there’s usually a chirpy Cock-er-ney navigator enlivening the journey with his fun commentary. A visit to Greenwich feels like a trip to a rather elegant seaside town—albeit one with more than its fair share of historic sites. The grandiose Old Royal Naval Hospital, designed by Christopher Wren, was originally a home for veteran sailors. Today it’s a popular visitor attraction, with a more glamorous second life as one of the most widely used movie locations in Britain.

Greenwich was originally home to one of England's finest Tudor palaces, and the birthplace of Henry VIII, Elizabeth I, and Mary I. Inigo Jones built what is considered the first "classical" building in England in 1616—the Queen's House, which now houses a collection of fine art. Britain was the world’s preeminent naval power for over 500 years, and the excellent National Maritime Museum> details that history in an engaging way. Its prize exhibits include the coat worn by Admiral Lord Nelson (1758–1805) in his final battle—bullet hole and all. The 19th-century tea clipper Cutty Sark was nearly destroyed by fire in 2007, but reopened in 2012 after a painstaking restoration.

Now it’s more pristine than ever, complete with an impressive new visitor center. Greenwich Park, London's oldest royal park, is still home to fallow red deer, just as it has been since they were first introduced here for hunting by Henry VIII. The Ranger's House now houses a private art collection, next door to a beautifully manicured rose garden. Above it all is the Royal Observatory, where you can be in two hemispheres at once by standing along the Greenwich Meridian Line, before seeing a high-tech planetarium show.

Toward north Greenwich, the hopelessly ambitious Millennium Dome has been successfully reborn as the O2 and now hosts major concerts and stand-up comedy gigs. More adventurous visitors can also go Up the O2 on a climbing expedition across the massive domed surface. Meanwhile, those who prefer excursions of a gentler kind may prefer to journey a couple of miles south of the borough, farther out into London’s southern suburbs, to the shamefully underappreciated Eltham Palace. Once a favorite of Henry VIII, parts of the mansion were transformed into an art deco masterpiece during the 1930s.