On the first Sunday in December, Park Avenue lights their Christmas trees on every corner in a ceremonial night. Families from all over the upper east side join with children on every set of broad, strong shoulders. For one night a year, the streets are closed to traffic and the sweet sound of children caroling “Rudolph the Red Nose Reindeer” reverberate across the avenue, a welcome reprieve from the honking and commotion that echoes through the city streets.