Sometimes it's nice to get away. Thanks to environmentalist Howard Zahniser, Americans can do that in one of the country's many wildernesses—areas sheltered from human activities. While conservation efforts like the creation of national forests and parks began in the late 1800s, untamed wilderness had dwindled to only 2.5% of the nation's land by the 1960s. To reverse this trend, Zahniser wrote most of what became the Wilderness Act. Signed into law by President Lyndon Johnson on September 3, 1964, it today protects more than 109 million acres—5% of the land in the US.