They think the eerie peak conceals a spaceship "garage" manned by extra"terrestrial beings.
Cult members pray the aliens will emerge to pluck them to safety in their craft when - according to the calendar of the ancient Maya civilisation of Central America - Armageddon comes on December 21.
We saw how hippies and New Age oddballs have thrown up makeshift camps in the shadow of the 4,040ft cloud"shrouded summit of the Pic de Bugarach in south"western France.
The mountain, with a network of deep caves, is thought to have inspired the Steven Spielberg movie Close Encounters Of The Third Kind and the classic novel Journey To The Centre Of The Earth.
But French authorities are less worried about the apocalypse than the impact of the cult invasion on the village of Bugarach - population 189 - at the foot of the peak.
Cops and troops have been drafted in to stop campers scaling the summit - a no"go area for five days from December 19.
But some of the end"of"the"world crowd say the military is really there to investigate dozens of recent UFO sightings.
They claim it suggests that the area is a hotbed of alien activity in the run"up to Doomsday - when the Mayan calendar's 5,125"year cycle finishes.
David, 30, who quit his telecoms job in the French city of Tours to live in a bus in a forest near Bugarach, told The Sun: "There are serious things going on here - I want to know what these objects are.
"These things exist and people have the right to know."
David, who did not reveal his surname, was not fully convinced that the world will end on December 21 but said: "I do think the capitalist system is going to collapse then."
Street artist and local children's co"ordinator Alain Didier insisted he had seen UFOs.
And Patrice Etienne, who runs an organic cafe in the village, is certain the mountain holds a major secret.
He said: "People walking on the mountain report that their cameras jammed when they tried to take pictures. They heard strange noises coming from underground.
"We have seen military aircraft, police and soldiers. It's like a Spielberg movie. They are looking for something. There is something in this mountain, definitely."
A government"backed anti"cult watchdog is warning against a repeat of the 1995 mass suicides by the Order of the Solar Temple sect in the Alps when their predicted Doomsday failed to take place.
Bugarach Mayor Jean"Pierre Delord said people have been spotted going up the mountain naked or in bizarre white outfits and carrying gold orbs to conduct rituals.
He said: "I'm not against people's beliefs but worry about the number of people coming because they think it's the end of the world."
Nicolas Martrenchard, cabinet leader for the local Aude region, led a delegation to Bugarach.
He said: "Some people don't want to give a thought to these apocalyptic end"of"the"world theories. I'm just here to make sure there is no threat to anyone's health or peace."
Villager Georges Tricoire, 72, shrugged: "I'll be here on December 22 and plan to get drunk."