The remains of what is said to be the largest Roman arcade in Britain are to go on show to the public.
The site, which is opposite Colchester Museum, consists of a series of 28 arches. It was discovered in 1954 but has only been exposed in recent years.
It was built in front of a massive temple dedicated to the Emperor Claudius in about AD50.
Philip Crummy, director of Colchester Archaeological Trust, said it was a "major archaeological monument".
The remains of three of the arches are to go on display in Castle House from the summer.
An information centre and cafe will occupy the rest of the ground-floor space.
The Colchester Archaeological Trust has been digging under the floor of the recently-built Castle House housing development, where part of the remains of the arcade has been uncovered.
Mr Crummy said the Roman arcade was the largest in Britain.
Colchester's Roman History
AD43 Britain's first Roman fortress established soon after the Roman conquest
AD49 Camulodunum, as Colchester was then known, becomes first Roman capital of Britain
AD54-60 Roman temple of Claudius built where Colchester Castle stands today
AD61 Camulodunum virtually destroyed during Boudicca's rebellion
"The new centre, with its display of Roman remains and animated reconstructions, will be a brilliant addition to the visible remains of one of the most important historic towns in Britain," he said.
Suki Dulai, chief executive officer of Flying Trade Group PLC, said the company bought the property eight years ago with "a view to opening a restaurant".
"However, after the discovery of Claudius Gateway, we've decided to preserve and celebrate our history with the community of Colchester," he said.