The museum sits inside Southampton's Grade II* listed civic centre, in rooms that used to be the magistrates' court and police station. The court left in 2001; the police followed in 2006, leaving a vacant block in the heart of the city. Wilkinson Eyre led the design, with a new pavilion extending the building - three interlocking bays of stone aggregate matched to the original Portland stone, the shape (as the Museums Journal critic Oliver Green put it) suggesting 'the prows of ocean liners cutting through art deco waves'. The whole project came in at £15 million, with about £5 million from the Heritage Lottery Fund. Construction was not straightforward. Contractors found significant corrosion in the original steel frame; integrating museum-grade security into a listed building took further work; topping out was held in August 2011, and the museum opened on schedule the following spring.

The permanent gallery 'Southampton's Titanic Story' is deliberately oriented around the crew rather than the first-class passengers. Most of the ship's crew - the stokers and trimmers, the stewards, the kitchen staff - lived in working-class neighbourhoods within walking distance of the docks. When the ship went down, entire streets lost husbands, sons, and brothers. The preserved courtroom inside the museum re-creates scenes from the British Wreck Commissioner's inquiry, where the disaster was picked apart witness by witness. Survivors' own audio recordings play through the galleries. Interactive elements let visitors try to steer the virtual ship or stoke its engines - the work the lost crew were doing when the iceberg hit. The civic centre's clock tower, glimpsed through a roof light at the entrance, is roughly the height of one of Titanic's funnels, a quiet way to suggest the scale of what sailed from Southampton that morning.

Southampton has been a port city for two thousand years, and the second permanent gallery, 'Gateway to the World,' takes the long view. The Romans built Clausentum here. The Mayflower set sail from Southampton in 1620 before being forced back into Plymouth by a leaky companion. Generations of emigrants - and later, post-war Caribbean and South Asian arrivals - passed through the docks. The collection now includes a seven-metre, one-tonne replica of RMS Queen Mary, rehoused from the old Southampton Maritime Museum, which closed in September 2011 so its objects could move here. The pavilion plays host to temporary exhibitions, opening with 'Titanic: The Legend' - a study of the ship's strange afterlife in pop culture, with Steiff mourning bears, beers from the Titanic Brewery, and clips from films stretching from 1912's 'In Nacht und Eis' to James Cameron's 1997 epic.

The story of how SeaCity got built is also part of Southampton's history. To close the funding gap in 2009, the city council proposed selling two works from the municipal art collection, including an Alfred Munnings oil painting called 'After the Race'. Opponents formed 'Save our Collection,' gathered more than 2,500 signatures, and warned that a sell-off would chill future donations. The artist Bridget Riley signed the petition; the Museums Association ruled the sale would breach its code of ethics. By February 2010 the council had backed down. The museum was built anyway, with help from the Wolfson Foundation, the Garfield Weston Foundation, and a Cultural Development Trust. Attendance has been uneven in the years since, but the Pevsner guide's quiet criticism - 'notably short of objects or artworks' - misses the point: this museum was never really about objects. It is about names.