Police in Paris discovered (in 2004) a fully equipped cinema-cum-restaurant in a large and previously uncharted cavern underneath the capital's chic 16th arrondissement.
Officers admitted they were at a loss to know who built or used one of Paris's most intriguing recent discoveries.
"We have no idea whatsoever," a police spokesman said.
Full story at: http://www.guardian.co.uk/world/2004/sep/08/filmnews.france