Champagne is the world’s best sparkling wine. It is not, however, the only type of bubbly out there. In fact, Champagne accounts for just a tiny fraction of all sparkling wine production, dwarfed by oceans of both Prosecco and Cava. So what’s the difference between them all? What makes Champagne so expensive, crémant so undervalued, and pét-nats so… unusual? Let’s break it down.