Six things to know about Queen Mary 2

The only remaining transatlantic liner, Queen Mary 2, has reached a milestone with its 450th crossing.

The record-breaking vessel left Southampton on Tuesday on the seven-day voyage to New York.

The Cunard flagship is an echo of the golden age of transatlantic liners from the early part of the 20th Century.

But how much do you know about its history?

Queen Mary 2 still holds records for being the longest, widest and tallest ocean liner ever built.

Designer Stephen Payne previously said its 345m (1,132ft) length was the most he could fit into Southampton Port's turning basin and at the New York piers.

It was also designed to fit just under New York's Verrazzano-Narrows Bridge, with a minimum headroom of 2.7m (9ft).

As a result, Queen Mary 2 has a shortened funnel, reaching a height above the waterline of nearly 62m (203ft).

When it entered service in 2004, it was also the longest and heaviest passenger ship in general, although those records have since been broken.

Payne said he convinced Cunard to create a purpose-built liner, not a cruise ship.

Queen Mary 2 is designed for long ocean crossings rather than port-hopping.

It has a thicker hull, a structural form fit for transatlantic storms and greater power and stability.

However, Payne said those choices meant less room for cabins and a need for extra steel.

That generated a 40% overall extra cost, he recalled.

Queen Mary 2 may be considered by some to be a British icon, but it is truly international.

The ship was officially named by Queen Elizabeth II after her grandmother, who was consort to King George V.

Based in Southampton, it follows in the wake of the QE2 and Queen Mary, both icons of British maritime tradition.

"Land of Hope of Glory" was sung at the ship's keel-laying ceremony in 2002.

However, construction took place at the St Nazaire shipyard near Nantes, France, and it was a French choir and orchestra who performed the patriotic Elgar song.

Cunard, a subsidiary of US cruise firm Carnival, paid an initial $800m for the ship, with millions more spent on subsequent refurbishing.

The liner frequently makes world voyages and its crew comes from more than 50 countries.

According to Payne, part of the ship's design was inspired by boyhood memories of Bournemouth beach.

He has said the front face of the upper decks is like a sandcastle, whose front has been washed away by the sea, leaving a conical shape.

BBC TV's Blue Peter also has a famous role in the ship's story.

When he was seven, Payne watched a report in which presenter Valerie Singleton said there would never be another big liner.

Payne wrote to the programme to tell them they were wrong and promised he would one day design one himself.

The editor replied with a Blue Peter badge and advised him not to be too disappointed if it never happened.

Not at all.

Queen Mary's 1,001 crossings between 1936 and 1967 are the most for a passenger liner. They include its service as a troop-ship during World War Two.

Another liner, QE2, made more than 800 crossings between 1969 and 2008.

Turnaround times in port have become faster over the years.

Queen Mary 2 is in and out of port the same day, often within 12 hours, while QE2's stops lasted for two or three days in its early years.

The liner's 2,600-or-more guests have a wide variety of entertainment and dining options.

It boasts the largest sprung dance floor at sea as well as the biggest ocean-going library, with more than 8,500 books.

Other entertainments include a nightclub, casino, theatre, cinema, five-a-side football, fencing classes and four swimming pools.

A dozen restaurants cater for a range of tastes and cabin classes.

The ship also claims to have the only ocean-going kennels, for passengers travelling with pets.