The 1825 Cellblock was the largest prison in the world at 476 feet long and originally four cells high and a total of 800 cells. Each cell designed for one man often housed two. About the size of a modern-day yoga mat, the cells were seven feet long by three feet wide and six feet seven inches high. Eventually, two more stories were added increasing the total cells to 1,000. The 1825 Cellblock was nicknamed "The Big House" and "Castle on the Hudson" and considered to be the best prison plan in the world.