This rare conical-roofed gas holder house in Saratoga Springs, New York is one of only 13 that still exist in the Northeast. As part of the Saratoga Power Company, which began in 1853, the gas holder house worked like this: coal gas was pumped into a tank that floated atop water. The tank rose and fell based on how much gas was present and its weight provided constant pressure to force the gas out through pipes, where it was distributed to the public. This process helped power the thriving resort city, but gas production operations were taken offline in 1928. In the additional photos, you can see how a couple more of these old gas houses have survived and been repurposed and now stand as an interesting roadside attraction.