In Epernay, the Champagne houses are mostly located on Champagne street; Avenue de Champagne. It's where the tourist office is too, (with very nice patterned glass doors) so we started at the tourist office end, and strolled down the street. The big names were there, as expected, and some we'd never heard of. There was a group of people outside of the Moët & Chandon establishment, and the shop looked open. We wandered into the compound to visit the shop, but the reason for the people present was that someone had set off the fire alarm, and everyone was outside. We wandered on.
There was an air of general celebration about the buildings, since the street has just been designated as a UNESCO World Heritage site. There were "Thank you" flags to be seen, the street looked exceptionally clean and the buildings were spotless.
The Champagne house that we visited was the De Castellane, not actually on Avenue de Champagne, but just aside from the end of it, because they have a tower you can go up and survey the surrounding countryside.
They also have a museum of Champagne-making, and one of printing, since the printing of bottle labels is an integral part of Champagne production. I'm fascinated by the straightforward concept that these complicated mechanical things actually worked, and that offset litho and Linotype machines were in regular commercial use while I was growing up.
Unfortunately the day was rather misty and the glass windows of the tower had condensation, so the views from the tower were limited. But you can get an idea of the intensity of grape farming in the area, from the pocket-handkerchief-sized patch in the photo.