The five new galleries at the popular event space have taken three years to create at a total cost of £20m, with £11.5m of that coming from the Heritage Lottery Fund.
These new event spaces will tell the story of London from 1666 up until the present day in including the Great Fire and the Suffragettes fight for voting rights.
They also include a 48m LED chandelier in Sackler Hall, which will host a newly commissioned film installation of life in the city by The Light Surgeons.
Other features in the new spaces will include an 18th century-style debtor's prison cell whose walls are inscribed with the graffiti left by unfortunate prisoners, recreated Georgian pleasure gardens where mannequins wear period costumes and specially commissioned masks and hats by Philip Treacy, and a war room complete with a suspended bomb.
One of the most impressive feature areas is an interactive river with architectural landmarks including St Paul's and the new 2012 Olympic stadia that allows visitors the opportunity to debate issues affecting London today.
London Museum director professor Jack Lohman said: "The Galleries of Modern London breathe new life into the Museum. It is thrilling to see our ambitious and complex project realised, transforming the Museum and placing it at the heart of the city it celebrates."
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