Top 10 Things You Didn't Know About National Parks

Not Your Typical Park
Forget lush forests, purple mountains and majestic wildlife. Some of the country's most popular national parks are important historic landmarks, like the Statue of Liberty and Alcatraz Island. Even the site of the 1995 Oklahoma City bombing falls under the care of the national-park system, which looks after the memorial and what is known as the Survivor Tree, a century-old Dutch elm that endured the blast despite having its trunk charred by flames and most of its branches torn off by the sheer force of the explosion.

• Ken Burns, American Filmmaker