A low-lying district where groundwater is conﬁned under pressure from surrounding layers of rock is called an artesian basin. These basins are often found where an aquifer (a water-bearing lens of earth) lies trapped in a syncline, or U-shaped fold, by impermeable layers above and below. When a well or rift breaks the surface, the subterranean water erupts upward. Artesian springs are usually reliable, unless the underlying aquifer is overtaxed by wells or otherwise drained. The Brown Palace Hotel in Denver possesses its own pure artesian well, freeing the hotel and its guests from the city’s chlorinated water system. The late Olympia (Washington) Brewery advertised its source with the slogan “It’s the water!” and launched an advertising campaign in the 1980s involving mythical creatures called Artesians. The term originates in Artois, the historic French province where such wells were ﬁrst described.