Harmony of the Seas, the world's largest luxury cruise ship took to the seas for the first time on Thursday afternoon as it slides into the waters of western France, in the port of Saint Nazaire.

However, the massive ship will have no passengers onboard as this will be its test run before its first official voyage from Southampton in Britain to the Spanish city of Barcelona in May.

Its mini test voyage is expected to end Sunday.

Well, how does the huge ship measure up to its precedents?

Weighing approximately 227,000 tons and 362 meters (1,187 feet) in length, the cruise ship is 50 meters longer than the height of the Eiffel Tower - and also 100 meters longer than the Titanic which measures a mere 269 meters.

Harmony is also a meter wider than the current twin ocean-going monsters of the pleasure cruise world, which are also 362 meters long.

"Allure of the Seas" and "Oasis of the Seas" were the world's previous biggest cruise ships in service, both being 65 meters wide and weighing 225,000 tons each. The trio belongs to Royal Caribbean International cruise lines.

Harmony also has 40 restaurants, many bars, shops, pools and a theatre.

The construction of the Harmony of the Seas began in September 2013 in the shipyards in Saint-Nazaire and was completed only recently.

2,500 people worked on the building of Harmony, and 90,000 square meters of carpet and 500,000 liters of paint was used.