A group of lay people, with the support of the Archdiocese of Philadelphia, has chosen the location of the city's first 'Mass mob' service, an evangelization effort calling area Roman Catholics to celebrate Mass at one location.

The service will be held March 23, during Lent, at Saint Francis Xavier, The Oratory at 24th and Green Street. The church is in the city's Spring Garden section and not far from the Philadelphia Museum of Art. The service is about a month before Easter, which falls on April 20.

Organizers say those planning to attend should arrive early - at least 15 minutes.

The service was planned by Mass Mob Philly, which is made up of members of the local Catholic community. It was the idea of a parishioner at St Francis Xavier, who received approval.  Although Archdiocesan officials embraced the idea, they did not organize it.

The Mass mob movement spread from Buffalo.  The idea was taken from flash mobs that, originally, were organized spontaneously with the idea of getting people together for a single purpose at a single time.  Flash mobs evolved into highly coordinated events.

Future Mass mobs in the area will be organized mostly through social media accounts such as Facebook and Twitter.  The Mass mobs will be coordinated with parish staff, with approval.

You can read more about Mass Mob Philly's efforts here.