The National Zoological Park is located a good bit north of the core area of D.C. but is very easily accessible via the Red Line of the Metro (at the Woodley Park stop).

The zoo stretches from Connecticut Avenue to the banks of Rock Creek and contains over 160 acres of habitats and park-like settings.  Despite potentially large crowds the zoo has plenty of spacious walkways and well-designed exhibits to allow plenty of viewers a good shot of what's going on.

For more information visit the official website by clicking here.