A 1m euro (£678,000) reward has been offered to help catch the arsonists suspected of being behind Greek forest fires which have killed at least 60.
Military helicopters have been used to fight the fires
Dozens of new fires continue to break out. Large swathes of Greece have been ravaged by the inferno since Friday.
Water-bombing aircraft from France, Italy and Canada are in action, with more international aid expected.
Ancient Olympia, birthplace of the Olympics, was in danger on Sunday, but firefighters managed to keep it safe.
Culture Minister George Voulgarakis went to Olympia, in the Peloponnese region of southern Greece, to oversee the emergency effort.
"All the people, the firefighters, the policemen, the volunteers, they fought with the fire and the museum is as it was."
The fires have gutted hundreds of homes, forcing thousands of villagers to flee and blackening hillsides.
The BBC's Dominic Hughes on the island of Evia, northeast of Athens, says several massive fires are burning in the thickly wooded hills and hot, dry winds are fanning the flames. On Sunday five bodies were found on the island.
Thousands of Greek firefighters are being supported by 20 water-bombing planes and 19 helicopters. At least 11 countries are helping Greece fight the fires with planes, helicopters and specialist firefighters.
Nikos Diamandis, a Greek fire department spokesman, told the Associated Press news agency: "Fires are burning in more than half the country. This is definitely an unprecedented disaster for Greece."
Prime Minister Costas Karamanlis has declared a nationwide state of emergency.
The reward, put up by the Greek government, is for anyone providing information which leads to the arrest of an arsonist.
"The reward is set between 100,000 and 1m euros for every [act] of arson, depending on whether death or serious injury occurred and the size of the damage," a Greek government statement said.
The fires could have been started as a way of getting around Greek law which forbids development on areas designated as forest land.
At ancient Olympia, flames licked the edges of the original Olympic stadium and scorched the yard of the museum, home to one of Greece's greatest archaeological collections.
Athens itself was shrouded in smoke that obscured the sun as several fires threatened the city's outskirts.
Peloponnese worst hit
The rapidly advancing fires caught many people unaware. Those who left the decision to flee too late were caught in their houses, cars, or as they stumbled through olive groves.
At least 39 people were reported to have been killed in the worst affected region, around the town of Zaharo in the western Peloponnese, by a fire that broke out on Friday and quickly spread.
Another four bodies were discovered in the central Peloponnese region of Arcadia.
A 65-year-old man has been charged with arson and murder relating to a fire which killed six people in Areopolis, in the far south of Greece.
Two youths were also detained on suspicion of arson in the northern city of Kavala.