Victorians
The age saw the introduction of the railway, allowing easy access and trade with London and the city expanded more than it had during the previous centuries.
This expansion in both housing and population led to several outbreaks of cholera; an outbreak in 1848 killed 34 citizens. There had been discussions on how to prevent this. One group sought to build a sewer system as they believed that hygiene was the key to prevention. They were opposed by the Muckabites, who did not agree that a sewer system would prevent the spread of disease (and who also did not agree with spending money from the city's public funds). National legislation led to the sewers being built in the 1870s.
Like the Romans, the Victorians loved to build (and like the Romans whatever they built, was built to last). A list of the more notable efforts are listed below.
The town hall (where the tourist office can be found) was built.
The statue of King Alfred by Hamo Thornycroft was erected in the Broadway in 1901.
The Peninsula Barracks was built. It was the headquarters of the Hampshire Regiment of the British Army.
The Royal County Hospital was built, Florence Nightingale, having been consulted on its design. Her grave, by the way, is just down the road, in Romsey.
The new suburbs that sprung up in areas such as St Cross and Hyde. If you have the time, it's worth strolling about these victorian suburbs.