The Romans built their city of Londinium and its walls 2,000 years ago, but only a few fragments still remain.

By the 3rd Century AD Londinium was one of the most successful Roman settlements in northern Europe.

One of the only remaining pieces of evidence of the Roman occupation is a small section of wall in the shadow of the Tower of London.

The wall once extended for two miles, and was six to nine feet thick and 18 feet high in places.

Another section of the wall that exists today can be found under the car park at Smithfield.

This section included a gate into the city with a guard house on either side.

In the Barbican area there was also a magnificent Roman fort which predates the wall by 100 years, and was later incorporated into it.

The walls set the shape of the city of London for the next 1,600 years.