The caves were carved into the Cerro de San Miguel, a hill composed of Miocene sandstone and conglomerate.
Excavations reveal that the chambers were likely used as living quarters, storage, and communal religious spaces during the Visigothic or Mozarabic periods.
The name 'Cien Pilares' (One Hundred Pillars) refers to the supporting rock pillars left behind by builders to prevent ceiling collapse.
Archaeological digs have uncovered remnants of pottery and silos, confirming the site's multi-functional history.
Some of the lower caves were historically repurposed by locals as dovecotes, known locally as 'palomares'.
The Cuevas de los Cien Pilares is a complex of man-made caves carved into the soft sandstone cliff of the Cerro de San Miguel in Arnedo. The site features a labyrinthine layout of chambers spanning multiple levels, connected by internal staircases and tunnels. Archaeologists suggest the chambers date back to the Middle Ages, serving as an early monastery or hermitage site. The name refers to the structural columns left behind during excavation to support the cave ceilings. It provides significant historical insight into troglodytic dwellings in the Ebro Valley. The interior maintains a consistent temperature throughout the year, protected by the mountain's geological structure.
From the elevated path looking back at the carved cliff face, capturing the scale of the cave openings.
Wear stable, non-slip footwear as the ground inside the caves can be uneven or damp.
Bring a light jacket as the cave temperatures remain cool even during hot summer months.
Reservations are typically required for access, as entry is managed through guided visits only.
Do not attempt to access the cliff area outside of the marked trails or guided tour route for safety reasons.
Visits are exclusively via guided tour; advance booking is required and schedules vary by season.
Do not touch the walls or historical carvings; remain with the guided group at all times.
