They're some of Greece's most celebrated beauties. And after nearly 2,500 years, it's perhaps only fitting that they're getting a face-lift.
The Caryatid statues, which until the late '70s propped up a section of the Erechtheion Temple on the Acropolis, are being meticulously cleansed of grime inside the museum where they're now housed.
Three goggle-wearing conservators zap away dirt from the marble maidens with custom-designed lasers, as tourists watch the operation on monitors. The restoration work is surrounded by a white fabric screen to protect visitors from laser beams, which can cause permanent eye injury.
One of the six Caryatids was removed by Lord Elgin in the 19th century and today stands in the British Museum. The other five were removed from the Erechtheion in 1979 to protect them from air pollution and acid rain, and replaced by copies.
Museum director Dimitris Pantermalis said the main reason for cleaning the sculptures on the spot was to avoid the potential hazards of moving them. But there's the additional value of offering tourists the spectacle of restoring some of the greatest glories of the ancient world.
"We want to offer visitors a backstage peek," he said.
Visitors are impressed: "The fact that it was in situ, taking place in the museum, it does bring it home to you the actual level of care that is needed to bring these back to life," said British tourist Trevor Richards, from Manchester. "It's like cosmetic surgery for statues isn't it?"
It takes about seven months to cleanse each of the larger than life-sized statues, which were carved around 420 B.C. Work began in 2011, and is expected to be finished in June.
"The process removes all of the pollution, the smoke and everything that has settled on the statues for more than a century, and leaves intact the patina, that orange hue that the statues took on with the passage of centuries," Pantermalis said. "It's done with very great care to avoid any possible damage."
The Erechtheion Temple was sacred to the gods Athena and Poseidon, and associated with the first kings of Athens. In later times, it served as a church, a Frankish palace and a Turkish harem.
Although Greece's oldest examples of pillars in the human form are a century older, the Caryatids are the most famous of their kind, and were widely imitated from Roman times to Europe's classical revival.
Conservators use technology developed specially for the Acropolis sculptures by the Foundation for Research and Technology-Hellas in Crete. The technique combines two infrared and ultraviolet wavelengths, to avoid causing discoloration or abrasion.
"The laser beam hits the black crust formed on the surface of the statues over the years, and that absorbs energy and disintegrates," said conservator Costas Vassiliadis, who heads the six-strong team. "The crust has a much lower resistance threshold than the marble, which is not affected."
Laser operators spend a maximum three hours on the job every day. Sometimes they get unwelcome intrusions.
"At first we felt slightly stage-struck, we tried to avoid making any noise, and always had in mind that we might disturb visitors," Vassiliadis said. "Only it's the other way round, as visitors several times draw back the curtain — which they really shouldn't as laser is dangerous for the eyes."