The countdown to the London 2012 Games began in earnest as the world watched the Olympic Flame being lit in ancient Olympia.
The traditional ceremony took place amid tight security in front of the ruins of the Temple of Hera in Greece, birthplace of the Ancient Games.
Dressed in classical robes, actess Ino Menegaki played the key role of the high priestess who lights the flame from the rays of the sun.
A 15-strong delegation from London 2012, led by Lord Coe, was invited to witness the ceremony at the temple.
The first torchbearer was Greek 10k world swimming champion Spyros Gianniotis, who was born in England.
He passed it to Alex Loukos, 19, who was one of 30 East End schoolchildren who travelled to Singapore in 2005 as part of the closing presentations for London's bid.
The flame will visit Crete, Piraeus, Thessalonica, Xanthi and Larissa, among other places, in a relay around the Greek mainland and islands.
The torchbearers are taking it from Olympia to the Panathenic Stadium in Athens, which held the first modern Olympics in 1896. The official handover to London 2012 will take place there on May 17.
Fourteen-time world champion gymnast Li Ning and Greek weightlifting hero Pyrros Dimas will be the last torchbearers in Greece.
They were chosen by the Hellenic Olympic Committee to symbolically link the last Olympic games in Beijing with Greece, the birthplace of the competition, and London.
It has yet to be revealed who the first torchbearers of the 70-day relay across Britain will be.
The relay, which will begin in Land’s End on May 19, will see the torch carried by 8,000 runners of all ages.
It will end in London ahead of the opening ceremony for the London Games at the Olympic Stadium In Stratford, on July 27.