DC Harbor Cruises, Washington

Departing from Washington Marina, a boat skipper begins another journey down the calm, flat waters of the Potomac River. The multi-decked, climate-controlled boats, such as the Freedom catamaran, power National Ferry Corporation's daily tours of the capital's famous waterway. The tour crafts are furnished with bars, snacks, full audio systems, and plush seating for sightseers to enjoy as they drift along the Potomac's smooth waters and collect eyefuls of national treasures. Guests can admire the imposing Capitol Building and whisper about how silly the Washington Monument looks without its powdered wig. The Coast Guard–certified staff points out other notable visuals such as the National Cathedral's stately towers, the Pentagon, and Fort McNair.