The underground of the city of Reims is hollowed out with deep cellars where the great champagne houses refine their precious bottles. Silent chalk cathedrals from the Gallo-Roman era linked together by galleries. In these old quarries, which vary in height from 10 to 35 metres, the humidity is 90%, without any condensation thanks to the absorbent power of the limestone. In summer and winter, the temperature never exceeds 50°F (10°C). A moderate and constant temperature which allows a slow foaming, an essential factor of the quality of the champagne.