Locog Chairman Lord Coe, International Olympic Committee president Jacques Rogge and Hellenic Olympic Committee president Spyros Capralos are in Olympia for the Olympic flame lighting ceremony.
Lord Coe and Jacques Rogge each received ceremonial gifts from the Hellenic Olympic Committee president.
The traditional ceremony took place in front of the ruins of the Temple of Hera in Olympia, Greece, the birthplace of the Ancient Games.
More top news
The Good Morning Britain host paid tribute to NHS staff for "fighting as hard as Derek is to give us the chance to be reunited".
There have been scenes of chaos in multiple cities, from Denver to New York, writes Robert Moore.
Most areas dry and warm with plenty of sunshine and light winds.