Epernay

The Avenue de Champagne is a kilometre of houses — Moët, Perrier-Jouët, Pol Roger — under which run more than a hundred kilometres of chalk galleries holding the region's reserves, which is why it has been called the most expensive avenue in the world for what lies below rather than above. Dom Pérignon was cellarer at Hautvillers, six kilometres north, and did not invent the bubbles.