The name, meaning “Forty Columns” in Persian, was inspired by the twenty slender wooden columns supporting the entrance pavilion, which, when reflected in the waters of the fountain, are said to appear to be forty.

As with Ali Qapu, the palace contains many frescoes and paintings on ceramic. Many of the ceramic panels have been dispersed and are now in the possession of major museums in the west. They depict specific historical scenes. […] There are also less historical, but even more aesthetic compositions in the traditional miniature style which celebrate the joy of life and love.Source: Wikipedia | Chehel Shotoun