Special curtains

Persiana

In Spain special curtains called "persiana" are pulled in front of the window to make house dark. I asked from a American guy translation for these special curtains but he did not know any word. I saw also persiana in Italy during my visit. Spanish people have wondered how it is possible to sleep if you do not darken the room with persiana. Before coming to Spain I was used to sleep also in a room which is not very dark but lets see if it is possible after sleeping months in a very dark room.