This year’s glorious show starts with a stroll through whimsical holiday exhibits that lead to the Conservatory. Marvel at G-scale trains as they chug along nine multi-level tracks, over bridges, under tunnels and through quaint holiday scenes set among colorful seasonal plants. 10 a.m.-3:45 p.m. Santa will be available to meet with children in his Holiday Cottage at scheduled times during each session; rain or shine; admission: $10 to $20. To choose dates and times, visit lasdonpark.org/shop/exhibitions/hoh21/holiday-on-the-hill-train-show.