Pictures of the deceased, food, sugar skulls, candies, alcoholic and non-Alcoholic Beverages, flowers and other items such as cigarettes, toys or any other stuff liked by such deceased. Additional decorations include strings of cempasuchilflowers (Mexican marigold) and paper cuttings (Spanish: papel picado) with many elaborate designs.
Those altars are FOR the dead, and according to the tradition, on the 1st and 2nd of November, they return to Earth to visit their relatives. As the altar is supposed to have candles (Spanish: cirios) guiding their way to the land of the living, they visit the altar and remember the 'good old days' when they were alive, by looking at and enjoying the items displayed there.
The Dead (Zombies) eats them during the night.
Day of the dead is a Mexican holiday that worships the dead
The relatives of the deceased.
They build an altar.
A couple of days before November 1st.
The Altar of the Dead was created on 1895-05-15.
It just means the altar is dedicated to such person; everything located on the altar -- flowers, meals and other personal belongings -- are there for him/her.
nov 1 and 2
At most, one or two weeks after November 2nd.
altar for dia de los muertos means an altar to the dead.
food
To make a special offering to the altar also known those who past away