The Norwegian Bliss is currently enroute to the west coast and is transiting the Panama Canal today. Doing so has made her the largest cruise ship, and largest ship by GT, to transit the canal.
The only other arguably larger ship is the container ship COSCO Development. That ship is 141,823gt and measures 1,200.79ft loa and 158.5 beam. The Bliss is 168,028gt and measures 1,069.2ft loa and 135ft beam. So the Bliss has her beat in gross tonnage but the COSCO Development has her beat by her dimensions.