For the Day of the Dead traditions (celebrated 1st and 2nd November), Ofrendas (offerings) are set up often in the form of an altar, to remember and honor the memory of those that have passed like the one shown below left and right;
These altars are typically decorated with pictures of the deceased, foods including Pan de Muerto, Marigold flowers called cempachucil, Papel Picado (such as the beautiful ones shown below by mexicansugarskull.com);
and of course, wonderfullly decorated sugar or papier mache skulls (such as those shown below by mexicansugarskull.com);