The Courier-Journal:

The final rehearsal for the lighting of the flame that will burn at the London Olympics went off without a hitch under sunny skies in the birthplace of the Ancient Games.
Standing in front of the 2,600-year-old Temple of Hera, an actress dressed as a high priestess used a concave mirror to focus the sun's rays and light a torch.
That flame will serve as a backup in the unlikely event that clouds block the sun at Thursday's official lighting ceremony. This has happened only once in recent memory for the Summer Olympics -- in 2000, ahead of the late-season Sydney Games -- but clouds have disrupted three of the previous four Winter Games ceremonies.
Read the whole story: The Courier-Journal