The 104 balsam firs that line Park Ave are more than just festive holiday adornments: The topiaries were first lit in 1945 in remembrance of those who lost their lives during World War II. The tradition continues to this day, and each tree is strung with 25 strands of white lights. The tree-lighting ceremony takes place on Dec 8. Park Ave between 54th and 96th Sts. Subway: N, Q, R to Lexington Ave–59th St; 4, 5, 6 to 59th St.