Founded in 1630, Boston is among the oldest cities in United States, and it's here that the American Revolution really got going. swords from the Battle of Bunker Hill and the Old North Church where two lanterns signaled the British on the move. Boston is also famous for baseball (the Boston Red Sox), basketball, swan boats and ducklings.
Ride the T - The subway in Boston is called the "T," and it was the first subway built in the United States. Ride the Green line, the original subway lines, twisting and turning as it goes underground. Using the T is the easiest way to get around Boston, including Cambridge. Purchase a CharlieCard, good for both the T and buses.
Harbor ferries - Ferries are an inexpensive way to take a boat ride and see Boston from the water. The Inner Harbor Ferry goes from Long Wharf (at the New England Aquarium) to Charlestown Navy Yard (and the USS Constitution). There are also commuter boats to Quincy and Hingham (children 11 and under are free). Pick up the ferries at Long Wharf or Rowes Wharf.
Here's our own Travel for Kids hand-picked list of family hotels, all styles and price ranges, convenient to fun things to do with kids in Boston: