ROME -- The Emperor Augustus said he found Rome a city of brick -- and he left it a city of marble.

But 2,000 years on, the cracks in his legacy are beginning to show.

The Forum, the Colosseum and the palaces of the Palatine Hill still stand as proud testament to the Roman builders' genius. Yet today they are betrayed by monumental neglect...

One of the latest closures came in November 2005, when a 16th-Century wall collapsed without warning in a well-visited area, near the Emperor Tiberius' palace. The collapse prompted officials to investigate the stability of the hill and its monuments.

The Palatine is honeycombed with cavities -- the result of centuries of tunnelling and digging. Instead of demolishing homes and palaces the Romans built on top of them.

So while the structures may look solid from above, below they rest on shaky foundations.

So dangerous have some of the structures become that now less than half of the Palatine Hill is open to the public.