In 1926, the US Post Office under the direction of Postmaster General Harry S. New, issued the first souvenir sheet in New York for the International Philatelic Exhibit. The special miniature sheet was comprised of 25 singe-design stamps commemorating the Battle of White Plains fought in 1776.
This sheet is considered one of the classic US "must haves" for any serious US collection. Condition of the sheet is extremely important since many of the sheets have been hinged or gum disturbances are very common. A very fine sheet can retail anywhere from $400-$600. Hinged sheets, or sheets with gum issues can retail significantly lower depending on where the hinging was done, the extent of gum damage, etc.