Puits de Jardel

The Jardel sinkhole extends 128 meters deep into the limestone terrain near Pontarlier, forming part of the regional karst geological complex.

In 1923, French military authorities deposited over 3,000 tons of unused World War I ammunition into the natural shaft for disposal purposes.

Local residents referred to the cavity as 'betise' until the 19th century, using it as a disposal site for deceased farm animals during epidemics.

Access to the sinkhole remains restricted by fences and warning signs due to the presence of unexploded ordnance and environmental protection measures.

The underground water level within the sinkhole fluctuates significantly during heavy rainfall, potentially affecting the submerged military munitions storage area.

Location: Chaffois

GPS coordinates: 46.91665,6.23873

Latest update: May 31, 2025 11:23