The National Zoo is pretty great, considering it won't cost you a single penny to walk around! There are plenty of habitats to observe and a few inside animal houses to keep your attention. The panda exhibit is quite popular, so be prepared for significant traffic if that is your destination. Food is available, but prices are pretty steep. Since there's plenty of food options outside and admission is free, I'd suggest grabbing a snack inside but getting lunch out of the park.
more