Falling chunks of mortar from Rome's Colosseum has rekindled the debate about the state of the Italian capital's archaeological treasures -- some of which are literally falling apart.

Three pieces of mortar -- measuring half a square meter (yard) -- collapsed at the weekend in the ancient amphitheatre, one of the most popular sites in Rome, plunging through a protective netting.

A restoration and cleaning project is set to start within the next month at the Colosseum, which was completed in 80 AD, but the city council is still struggling to raise all the funds needed from the private sector and from donors abroad.