The centrepiece of every celebration is a beautifully decorated altar. Families spend days preparing it - arranging flowers, hanging paper garlands, placing candles, and putting a figure of the Virgin Mary at the centre surrounded by offerings. Each altar is unique, and neighbours visit each other's homes to admire them.
The call-and-response shout is one of the most fun parts. The host calls out '¿Quién causa tanta alegría?' - 'Who causes so much joy?' - and all the visitors shout back '¡La Concepción de María!' ('The Conception of Mary!'). This is called 'La Gritería', which means 'The Shouting'. The noise fills the streets and everyone laughs.
After the shouts come the treats. Hosts give out bags full of goodies - sugar cane, tangerines, peanuts, jícaras (little painted gourd bowls), sweets, and small toys. Children go from house to house filling their bags. It has something of the feel of Halloween trick-or-treating, but in December, with singing instead of costumes.
La Purísima is celebrated across Nicaragua but especially enthusiastically in León and Managua. On the big night of La Gritería (December 7th), the streets are crowded, fireworks go off, and the shouting from every direction creates a joyful noise unlike anything else. It is a festival that every Nicaraguan remembers from childhood.