Grand opera is a genre of 19th-century opera generally in four or five acts, characterized by large-scale casts and orchestras, and (in their original productions) lavish and spectacular design and stage effects, normally with plots based on or around dramatic historic events. The term is particularly applied (sometimes specifically using in its French language equivalent grand opéra, ) to certain productions of the Paris Opéra from the late 1820s to around 1850; 'grand opéra' has sometimes been used to denote the Paris Opéra itself.