’Twas the night before Christmas, when all through the zoo, not a creature was stirring—not even the black howler monkeys, sea lions, and kangaroos. Every winter, the Houston Zoo and its more than 6,000 animals get that festive feeling when the park undergoes its annual holiday makeover: Zoo Lights. During this Houston tradition (Nov. 18-Jan. 14, closed Christmas Eve and Christmas), staff will flip the switch and illuminate more than 2 million lights—a 15-mile display of eco-friendly LED lighting presented by TXU Energy. Visitors can enjoy festive carols, hot chocolate, and Holly Berry: a 1958 Cadillac with a lightshow set to music. Last year ushered in a new tradition: a 33-foot-tall Christmas tree adorned with colorful decorations—the ideal backdrop for holiday selfies.