June 19, 2008--Flames illuminate thousands of revelers in a cave in Zugarramurdi, Spain, during a 1998 Aquelarre, or Witch Coven.

Held on or near the summer solstice, the festival commemorates the alleged witches who used the cave in centuries past--many of whom died by fire during the Basque witch trials of the 1600s.

For millennia the summer solstice has been embraced as a time of rebirth and hope, and as a herald of abundant food and warm temperatures to come (summer solstice facts).

Falling this year on Friday, June 20, in the Northern Hemisphere, the longest day of the year is still regarded by many as a day of mystical and religious significance--and the cause for many a celebration.