An archaeological dig to unveil the full history of the 2012 Olympics site has begun in east London.
The site may unearth items from Roman and Viking times
Experts from the Museum of London have begun researching the Roman, Viking, medieval and recent industrial history of the 500-acre site.
David Higgins, of the Olympic Delivery Authority, said: "This is an opportunity to chart and record the unique history of the area."
Any remains will be recorded or moved to the Museum of London.
The exercise is aimed at identifying remains buried underneath top soil and rubbish on the Stratford site.
"Work will be carried out by experts and hopefully more clues to the Lea Valley's past will be found," Mr Higgins said.
"We are starting well ahead of the planned start of construction and nothing is expected to be found that could affect our timetable."
Twelve trenches up to four metres deep are to be dug on the north-east corner of the site on Thursday near a Second World War gun emplacement and a medieval waterway.
Kieron Tyler, senior archaeologist at the Museum of London, said: "This investigation will tell the story of the changing landscape and exactly how human intervention has constantly influenced the environment.
"It is a unique opportunity to do it on such a huge scale."
Meanwhile, Olympics organisers have asked for people whose lives have been inspired by the Games to take part in a film which will be used to promote the event.
Casting teams from the 2012 Olympics will be in Belfast, Glasgow and London interviewing people over the next few days.