(RNS) Bonfires, drum circles, dancing, candlelit meditation and other ceremonial rituals help usher in the summer solstice at the annual Pagan Spirit Gathering, now in its 30th year in the United States.

Along with celebrating the longest day of the year on Monday (June 21), this year’s weeklong festival at a campground in Salem, Mo., will also feature prayers to help the Earth recover from the BP oil spill in the Gulf of Mexico.

“We always do planetary healing prayers, meditations, and ceremonies on Solstice day itself, and we will be continuing our prayers about the oil disaster,” said Selena Fox, a high priestess at Circle Sanctuary, a Wisconsin-based pagan resource center.

“We will explore ways that the various organizations and traditions represented at our gathering can support relief efforts.”

The most famous Solstice celebration draws tens of thousands of revelers to England’s ancient Stonehenge monument every June; the Missouri festival, which runs June 20-27, will be the largest organized event in the U.S., Fox said.

Nearly 1,000 people are expected to attend from North America, Europe and Asia, including practitioners of Wicca, contemporary pagan, Druid, Celtic, Native American, Afro-Caribbean, and Taoist faiths.

The main Solstice ritual will feature chanting from 18 Circle Sanctuary ministers, intended to “help heal the wound in the earth,” Fox added.