My son’s eyes and mouth went wide when he spotted the blue tree. Festooned in lights, it was far from anything natural, but it was sure pretty. This past Sunday, we attended ZooLights, an annual month-long event at the National Zoo that turns it into a winter wonderland.

Trudging up the big hill to the Zoo from the Metro station, I yelled, “The lights! We’re almost there!” We were greeted with a wall of sparkling blue, transforming into a melange of additional colors as we got closer. A sign proclaiming ZooLights featured a red panda wagging its tail, a likeness of the naughty animal that escaped the Zoo last year.

While most of the real animals were sleeping, a whole menagerie awaited us in lights. Hummingbirds flapped their wings, snakes swayed, lizards smacked flies with their tongues and an eagle joined its mate in a high-up nest. My favorites were the surreal ocean animals and the quirky naked mole rats. Sprout seemed to like the anteater slurping up ants as they came out of their hill, although he shied away from the snake.

We did see one animal, although it was sleeping. We received a stuffed bison from my uncle for Christmas, so I wanted to show Sprout a real one. Unfortunately, as Sprout said, he was “a little scared” by its size. While he had nothing to be afraid of at the zoo, that will serve him well if he ever visits out West at least.

But Sprout’s favorite part wasn’t even inside anyway – it was the model train display inside the main visitor’s center. Thomas and Friends, along with a Lego train, chugged by zoo animals, miniature town halls, storefronts, fishermen crabbing, and even chefs breaking down the seafood on the beach. Sprout could have stood there all night if we’d let him. Judging by the crowd of kids against the fence separating them from the trains, he wasn’t the only one.

The Visitor’s Center wasn’t the only busy place – the whole zoo was pretty full. While the event is normally very popular, the 60-plus degree weather really drew out the crowds. I’d imagine there were long lines to get food or go on the rides (like carousel or slide), but it was fine if you just wanted to see the lights. We only noticed it when there was a bottleneck.

We ended up seeing a little less and leaving a little earlier than expected because Sprout was falling asleep in his stroller. While he usually likes to get out and walk around a bit, he just responded with a sigh and “no” whenever we asked. His eyes were fluttering when we got back to the Visitor’s Center, where we planned to change him into pajamas in the hope he’d sleep on the train ride home. Of course, that was invigorating and he didn’t come even close to falling asleep until we put him in his crib.

However, his newfound energy did come in handy when he and Chris caught sight of “Panda Claus,” a person in a panda bear outfit with a Santa hat. Sprout thought high-fiving the panda was just fantastic and mentioned it several times on the way home. I suspect he was a bit disappointed when I showed him the actual, cute but kind of boring pandas on the Zoo’s PandaCam yesterday morning.

Besides the lights themselves, one of the things I like best about ZooLights is the price -free!  It’s easier on my wallet, which is nice, but it also opens it up to a lot of families who might not be able to participate. A lot of Christmas activities are astoundingly expensive – looking at you, Ice at the National Harbor – so it’s great that this is open to everyone.

While we don’t have too many Christmas traditions yet, visiting the ZooLights is very likely to become one of them. In fact, we’ve already promised Sprout that we’ll be back again next year.