The rave party in Cornusse in central France will last all weekend, according to the organizers - who estimated that between 35,000 and 40,000 participants gathered on Saturday evening.
But the regional government is issuing sharp warnings as the site "is extremely dangerous, as explosive ordnance may be present there," according to Philippe Le Moing Surzur, the head of the department.
Modern ammunition poses no danger, he said, but old ammunition can detonate.
The place has been used for 150 years, and we know that there may be ammunition in the area, said Le Moing Surzur, appealing to dancers to avoid forest areas where the risk of hidden duds is higher.
