Launched last year, the Million Mask March was organised by the hacktivist group Anonymous to protest at a huge range of issues from government corruption to NSA spying and war crimes.
On 5 November 2013, marches took place at over 400 locations around the globe, with thousands of people gathering in London to take part in the march - including comedian Russell Brand. The event was organised to coincide with Guy Fawkes Day, reflecting the iconic Guy Fawkes mask which has become a symbol of Anonymous.
The event in London last year was peaceful for the most part but there were 15 arrests with some protesters turning violent when the large police presence tried to remove them.
Some of the protestors were also arrested for starting a fire in front of Buckingham Palace
The 2014 running of the event will be under the banner of Operation Vendetta, one of Anonymous' on-going campaigns protesting against government corruption.
"November 5th is a day of international rebellion against oppressive governments, on this day, Anonymous UK will unite with the world wide collective and take to the streets for a protest like none that has ever been seen in history," a video announcing the second Million Mask March said.
The event in London will begin at 6pm on 5 November at Trafalgar Square and like last year is likely to move down Whitehall to parliament.