The Day of the Dead (or Dia de los Muertos) originates from around 4000 years ago, before Mexico even existed as a country. The festival's roots stem from the common belief in the afterlife held by the Olmec, Mayan, Aztec and other Mesoamerican civilizations. It is because death is seen as a continuation of life that it is celebrated in such a manner on All Saints' Day and All Souls' Day.
Mexico (and a host of other countries) celebrate Day of the Dead as a holiday on November 1 and 2 each year, honouring their loved ones and ancestors who have passed away in festivities that are both uplifting and inspiring. It is believed that the gates of heaven are opened at midnight on October 31, and the spirits of all deceased children are allowed to reunite with their families for the day.
The following day, known as All Souls' Day, is when adult spirits come to join in the celebrations laid out in their honour. It is on this day that you will see the true Mexican attitude towards life and death. This cycle of life and death is seen as natural and, of course, inevitable, yet death is widely seen as something to be defied, resisted and even mocked and this is done through the festival. This is all typified by the traditional message: "Don't take anything lying down - even death".
Whilst this attitude towards death may be something completely new to you, you'll undoubtedly develop an appreciation for this deep-running defiance towards death that is overtly portrayed. Family altars are lavishly decorated - including offerings of their favourite food and drink, candles and incense are lit and then people eat and drink in a party atmosphere. This is until 6pm, when the bells toll to summon the dead, ringing solidly throughout the night until sunrise, during which time the party doesn't stop.
Visitors are often introduced to this festival via handicrafts as a way of teaching the meaning of the days and their importance to the locals. These included paper mache skeletons and candy skulls, typically intended for the souls of departed children to enjoy. Pan de Muertos (Day of the Dead bread) is decorated with skeletons and are frequently used as a centrepiece for altar decorations, with extra bread shared with mortal guests present.
However you choose to celebrate or observe such an amazing tradition, it is important to remember that the dead are not mourned for, or even necessarily celebrated, but are really considered to be present throughout which might be the reason that this is one of the most uplifting festivals you will ever attend.