Cheetahs!
The zoo is free, and a vigorous walk from the Metro station (parking is available but discouraged).
Cheetahs. The pandas are there, but they sleep during the day for the most part. The cheetahs frolick all day.
There are some steep hills--keep that in mind if you have kids. You can spend an entire day in DC at the zoo.
The animal houses are a bit dated but the pros outweigh the cons.
Did I mention the cheetahs?

A great zoo and the first time I was there wasnt long after the Pandas arrived!

Well, it's free. That's a plus. It's also kid-friendly and a couple of blocks from the Metro. But it isn't close to being a first-class zoo compared to better zoos in our nation. Shouldn't the capital zoo be more special? Plus, the place was a little dirty.

A great zoo. I was very impressed by the design of some of the pens, it almost seemed like you could reach out and touch some of the animals. We were also fortunate to be visiting at a time when the Pandas were being active and playful, and right up front, too. The only drawbacks are the lack of restrooms (We always seemed to be a really long walk away from one when we needed it) and the outrageous price of lunch at the Mane Restaraunt. But, what can you do when you're a captive audience?

below average zoo, aging exhibits.

Are we talking about the one with animals or Congress?

The zoo is nice, and free admission is a plus. It is a long walk from the Metro, and oftentimes your time at the zoo depends on the animals.

I'm from D.C, and I've been to a handful of zoos around the country and even overseas (switzerland). I gotta tell ya I don't think anyone treats their animals better than the National Zoo. When I went to california this past summer, I was expecting to be blown away by the San Diego Zoo. They certainly did have a wider range of interesting animals, but for example, their big cats have really tiny spaces.. I usually judge a zoo by how their big cats are kept. And at national zoo they have the most ingeniusly designed cat pens, that give them plenty of space in which the viewers are also out of jumping range. The other large animals such as bears and pandas have an impressive amount of room, too.

OK nice zoo - go see the real sites - every city has a zoo but no city has The National Mall with all of the Memorials

No zoo is to my liking, but the National Zoo is a good size with a good variety of animals, and they mostly appear to be content.

The National Zoo sucks because you never see the animals.

I love the zoo, but th Audobon Zoo in New Orleans is much better than the National Zoo. The pandas would never move and that was the most advertised attraction when I was younger.

Well designed and FREE!

It's a great zoo but there are a lot of hills so don't go on a really hot day.

National Zoo is a cute place to bring a family, but its not as nice as the Philly or Bronx Zoo.