ZooLights at the National Zoo features eco-friendly lights on trees, walkways and animal-themed statues. Admission is free. (Mehgan Murphy/National Zoo)

The National Zoo is pretty cool any time of day, any time of year.

But this is a special time of year when you can enjoy the zoo after dark when it’s all ablaze in holiday lights.

Thousands of eco-friendly lights decorate the zoo’s trees, walkways and buildings. Life-size animal light statues dot various parts of the zoo. And you get the rare chance to see the zoo’s residents after the sun has set.

Don’t miss the visitor center where you can see the Zoomagination Train Station featuring an old-fashioned steam engine, the always-popular Thomas the Tank Engine and animal figures. For real train lovers, take the special trackless train ride through the tiger and lion habitat to see special lights. There’s even a skating rink. Just don’t call it an ice skating rink. That’s because this rink is made of eco-friendly materials that let you glide across the surface, which is recyclable.

If you get chilled with all the walking around, duck into the small mammal house or the Think Tank. Those and other exhibit houses will be open during ZooLights.

What: ZooLights

Where: National Zoo, 3001 Connecticut Ave., Washington

When: Dec. 4, Dec. 9-11 and Dec. 16-Jan. 1 (except Dec. 24, 25 and 31). 5-9 p.m.

How much: Admission is free; parking is $16. The train through the big cat habitat is $3, and skating on the iceless rink is $5 for 30 minutes.

For more information: www.nationalzoo.si.edu/activitiesandevents/celebrations/zoolights/default.cfm