When someone that u know dies,for them they don't believe that they are died but they know so that's the day they celebrate the day of the people that they love death
Day of the dead is to celebrate family and friends and also strangers who have passed lives. It is to celebrate life and welcome the dead as they visit as ghosts. Many people use face paint to look like sugar skulls, so the dead don't feel unwelcome. There are huge parties and parades, and if you watch the movie, The Book of Life, you might catch on to what this holiday means.
