Carnival president Christine Duffy tells USA TODAY the line plans one of the attractions for the 5,200-passenger Carnival Mardi Gras, the first of a new series of giant vessels that will begin ...

To make sure guests don't feel crowded or caught in long lines on the line's largest-ever ship due in 2020, Carnival has been hard at work engineering the flow of people around the 15-deck vessel.

The Mardi Gras has 18 decks, including a two-story atrium lobby and a three-deck promenade. The accommodations include 2,641 staterooms, including 1,130 balcony rooms and 44 suites.

Carnival Cruise Line's giant new ship, the Mardi Gras, will begin sailing from Port Canaveral in October 2020, with a range of seven-day Eastern and Western Caribbean cruises.

A rendering of the Mardi Gras' top deck. ... More than 40,000 guests have been notified that their plans have been changed. ... The Carnival Mardi Gras is also being built in Turku.