In pre-Christian Europe, Puy de Dôme served as an assembly place for spiritual ceremonies. Temples were built at the summit, including a Gallo-Romantemple of Mercury, the ruins of which were discovered in 1873. In 1648, Florin Périer, at the urging of Blaise Pascal, supported Evangelista Torricelli's theory that barometric observations were caused by the weight of air by measuring the height of a column of mercury at three elevations on Puy de Dôme. In 1875, a physics laboratory was built at the summit. Since 1956, a TDF antenna is also located there. On the top of the mountain, there is a transmitter for FM and TV.
Tourism
The Puy de Dôme is one of the most visited sites in the Auvergne region, attracting nearly 500,000 visitors a year. The summit offers expansive views of the Chaîne des Puys and Clermont-Ferrand. It is a well-known centre for paragliding. The summit can be reached by two pedestrian paths: a southern one and a northern one which runs past the Nid de la Poule'' crater. The GR 4long-distance trail includes both paths to cross the mountain. Since May 2012, visitors can also go up the mountain by train with the Panoramique des Dômes, a rack railway. A road exists along the train tracks but it is closed to the general traffic, except forthe military, service vehicles or emergencies. At the top of the mountain, restaurants and shops are available as well as a visitor centre giving information on the history and geology of the area.
Sport
Cycling
In more recent times, Puy de Dôme has served as an occasional stage finish in the Tour de France. It was here that in 1964Raymond Poulidor battled with Jacques Anquetil in one of the race's most famous moments, racing side by side up almost the entire climb; and that in 1975Eddy Merckx was punched in the kidney by a spectator. According to Jean-François Pescheux, since the construction of a rack railway, and because of the very narrow road, the Tour will never come back to the Puy de Dôme, its last ascent in the race being in 1988. The road is open to cyclists only during very limited periods. In 2006 this was 7–9am on Wednesdays and Sundays between 1 May and 30 September. In 2017, it will be the first checkpoint in the Transcontinental Race, which is a nonstop, unsupported bicycle race across Europe.
While the lower areas of the mountain are firmly oceanic, Puy de Dôme has a humid continental with borderline subalpine characteristics, thanks to its high elevation. Its classification is determined from its January average being well below the -3° threshold, and for having over 4 months of average temperatures that exceed 10°.