Mexican parties, or fiestas, are traditional celebrations that involve music, dancing, food, and drinks. They are often held to commemorate important events such as weddings, baptisms, and birthdays. Fiestas are also used to celebrate religious holidays, such as Christmas and Easter, as well as national holidays like Cinco de Mayo. The atmosphere of a fiesta is usually lively and festive, with people dressed in colorful clothing and decorations adorning the area.