Restoration on the Acropolis has been going on for years. It is not easy to repair the marks of centuries of warfare, human abuse, earthquakes, fires, not to mention the latest nemesis of the monuments, pollution.
Here we see a restorer carefully cleaning the interior of the walls of the Erechtheum, on the Acropolis.
The restoration project began in 1975, and still has a long way to go. Work at the Propylaia (the monumental gate) and the temple of Athena Nike has been completed, but the Parthenon restoration, by far the most complicated due to the severe damage to the temple, will take years to complete. For more information, see here.