Boston's commercial and Financial districts—the area commonly called Downtown—are concentrated in a maze of streets that seem to have been laid out with little logic; they are, after all, only village lanes that happen to be lined with modern 40-story office towers. Just as the Great Fire of 1872 swept the old Financial District clear, the Downtown construction in more-recent times has obliterated many of the buildings where 19th-century Boston businessmen sat in front of their rolltop desks. Yet many historic sites remain tucked among the skyscrapers; a number of them have been linked together to make up a fascinating section of the Freedom Trail.
The area is bordered by State Street on the north and by South Station and Chinatown on the south. Tremont Street and the Common form the west boundary, and the harbor wharves the eastern edge. Locals may be able to navigate the tangle of thoroughfares in between, but very few of them manage to give intelligible directions when consulted, so you're better off carrying a map.
Washington Street (aka Downtown Crossing) is the main commercial thoroughfare of downtown Boston. It's a pedestrian street once marked by two venerable anchors of Boston's mercantile district, Filene's Basement (now closed for a several-year-long face-lift) and Jordan Marsh (now Macy's). The block reeks of history—and sausage carts. Street vendors, flower sellers, and gaggles of teenagers, businesspeople, and shoppers throng the pedestrian mall outside the two buildings.
Downtown is also the place for some of Boston's most idiosyncratic neighborhoods. The Leather District directly abuts Chinatown, which is also bordered by the Theater District (and the buildings of New England Medical Center) farther west, and to the south, the red light of the once-brazen Combat Zone flickers weakly in a pair of adjacent strip clubs. The Massachusetts Turnpike and its junction with the Southeast Expressway cuts a wide swath through the area, isolating Chinatown from the South End.
This section of Boston has a generous share of attractions, so it's wise to save a full day, spending the bulk of it at either the New England Aquarium or the Children's Museum. There are optimum times to catch some sights: the only tours to the top of the U.S. Custom House are at 10 and 4 on sunny days, and a stroll along the waterfront at Rowes Wharf is most romantic at dusk. No need to visit the aquarium at a special hour to catch feeding time—there are five of them throughout the day.