The Royal Armouries has unveiled its new-look museum at Fort Nelson on Portsdown Hill near Fareham, Hampshire, following the completion of an extensive £3.5m overhaul.
It is hoped the investment in the attraction will attract tens of thousands of visitors each year and has included the creation of a new glass-sided gallery - Voice of the Guns.
New exhibitions exploring the history of the fort and its people; a new education centre; and a visitor centre housing Café 1871 have also formed part of the redevelopment.
Work commenced on site in August 2010, with Mansell appointed to deliver the renovation. The Heritage Lottery Fund (HLF) contributed more than £2m towards the scheme.
Jonathon Riley, director general and Master of the Royal Armouries Lieutenant-General, said: "I am sure [the museum] will entertain and educate hundreds of thousands of visitors for decades to come.
Stuart McLeod, head of the HLF in the South East, said: "Fort Nelson's new state-of-the-art galleries are a fitting home for its comprehensive artillery collection, enabling the story of Portsmouth's role in both World Wars to be told properly for the first time."
Details: www.royalarmouries.org