The Fountain stands on the grounds of the Royal Palace in the Emerald City. Clear, sparkling water bubbles up in its golden basin, but it bears a sign that reads, "All Persons are Forbidden to Drink at this Fountain."
Centuries ago, a wicked king ruled the Land of Oz and made himself and his people miserable and unhappy. Glinda placed the Fountain in its present location, and the king drank from its water. His people still feared him, so he made them drink from the fountain as well. Then the king and his people grew wise together. That king placed the warning sign on the Fountain to prevent anyone from drinking of it by accident.
Some later Oz writers have found the Fountain irresistibly tempting. It is the crucial element in the McGraws' The Forbidden Fountain of Oz. It also plays important roles in Jack Snow's The Shaggy Man of Oz, Rachel Cosgrove Payes's The Wicked Witch of Oz, and Edward Einhorn's Paradox in Oz.