Mount Redon, Volcanic summit in Puy-de-Dôme, France

Mount Redon is a hill by the village of Ponteix, in the commune of Aydat, formed by an old basaltic volcanic chimney from the Tertiary. Its upper slopes are covered with bare trees and low scrub, with pale grey boulders and rock outcrops among dry brown vegetation. Near the base, reddish-brown bracken alternates with green grass, and the summit holds the ruins of the castle of Montredon, whose most visible remains are the lower courses of the enclosure walls and towers on a cliff of basalt prisms.

Bishops of Clermont built a castle on the summit in the 13th century to control the surrounding region. The fortress was destroyed in 1587, but traces of it remain visible at the top.

The summit's name survives in the ruined Château de Montredon, held in the 13th century by the bishops of Clermont, who granted it as a fief to the lord of Montgâcon. The parish church that stood at the foot of the castle was demolished in 1867, and some of its stones went into the church of Ponteix, in the commune of Aydat.

Marked yellow trails lead from Ponteix village toward the summit, taking about two to three hours to reach the top. The terrain is fairly steep, so sturdy footwear and drinking water are important for the hike.

Inside the rock is a preserved ancient volcanic chimney from the Tertiary period, showing how magma flowed through the mountain millions of years ago. This geological feature gives visitors a rare look at what lies beneath the surface of a dormant volcano.