1 The Mall
It's not so much that Washington has so many magnificent neo-classic monuments, memorials and government edifices, it's that the city fathers had the foresight to plan for all of them and the blessing of being able to start from scratch. The world's first planned capital is the work of Frenchman Pierre L'Enfant, who based the city's grid pattern and broad diagonal avenues on his aesthetically irreproachable home, Versailles. Two hundred years later, the dramatic sight-lines envisioned by L'Enfant are an aesthetic reality, especially along the 1.6km open greensward that runs from the US Capitol through the Washington Monument and on to the Lincoln Memorial, with the Jefferson Memorial and the White House opening up to the north and south respectively. So get out and start walking - and keep walking until you've seen it all. Then come back at night to see it again - all bathed in soft white arc lights.
2 The National Gallery of Art
3 Downtown
Many first-time visitors are surprised to learn Washington has a separate commercial 'downtown'. It occupies the literal - if not symbolic - high ground north of the Mall. While not destined to win many architectural prizes, Washington's functional, mostly postmodern, downtown is not without its charms, including the wide avenues (named after states) that interject interesting angles into what would otherwise be a boring grid, and the numerous squares, parks, and circles that provide physical and visual relief. And as no building is allowed to be taller than the dome of the US Capitol, downtown Washington is devoid of the oppressive shadows and canyons of, say, a New York or Chicago. A midday stroll along K Street (aka Gucci Gulch) is guaranteed to have you cross paths with Washington's infamous - but little recognised - legion of lobbyists, consultants, and influence peddlers on their way to and from power lunches or senior-level negotiations. By evening, it's a hive of mid-level activity as office workers descend for happy hour, dinner or a little upmarket shopping before retreating to their homes in the outlying suburbs.