Girls participate in a mass Quinceanera celebration in Mexico City April 30, 2011. More than 400 girls from around the country were invited by Mexico City's mayor to dress up for their Quinceanera, a "coming of age" celebration on their 15th birthday. The "coming of age" celebration is a tradition dating back to the Spanish colonial era, when girls would make their official "debut" in society as 15- and 16-year olds.