Possible Clues:

• Rialto Bridge sight
• Cut through Panama
• By way of water, Pa might get to the North to get Ma for one of such
• Is a fifty enough to allow one to barge around in?
• Is a half-century able to barge along here?
• Part of a network, often
• See 51-Across
• Ship's shortcut
• Lake-to-lake link
• Artificial waterway for barges