The remains of the largest Roman chariot racing track outside Italy may have been found under an army barracks being redeveloped in Colchester.
Archaeologists are studying the site to determine its significance
New homes are going up on a 209-acre site where builders preparing the groundworks excavated what they believe is a 2,000-year-old race track.
Developers Taylor Woodrow said they are asking Essex county archaeologists to judge if their suspicions are right.
A spokesman said: "It will be a great find if it is proved to be true."
The project may be delayed if archaeologists decide to carry out a full excavation and investigation.