From their event page: 

The Wanamaker Light Show presented by PECO is a Philadelphia holiday tradition dating back half a century, housed in the historic Wanamaker Building. The free show uses more than 100,000 LED lights to project snowflakes, ballerinas and reindeer upon a four-story-high velvet curtain in the Grand Court atrium, accompanied by festive music from the world-renowned Wanamaker Grand Organ.

The Light Show will run every hour on the half hour beginning at 12:30 p.m. each day of operation, with select plays accompanied by live performances of the historic Wanamaker Organ (expect Sundays). Additionally, Wanamaker Organ concerts will follow the Light Show twice per day, at approximately 12:45 p.m. and 4:45 p.m. (12:45 p.m. ONLY on December 24).

Floors above, is another holiday tradition: Dickens Village. The 6,000-square-foot walk-through experience transports visitors to 1840s London with 26 heart-warming scenes from A Christmas Carol and is available with free timed-tickets. Tickets will be available here 5 days in advance of each date starting November 24th.