Record visitor numbers at the nation's first national park have transformed Yellowstone National Park's annual tourist rush into a sometimes dangerous frenzy.

Photo-snapping visitors routinely break the rules, getting too close to elk, grizzly bears, wolves and bison.

Officials say the rule-breaking puts visitors in harm's way, damages resources and displaces wildlife.

Law enforcement records obtained by The Associated Press suggest such problems are on the rise.

Yellowstone rangers are seeing more wildlife violations, more people treading on sensitive thermal areas and more illegal camping.

It's an illustration of the pressures facing America's most treasured lands as the National Park Service marks its 100th anniversary. From the Great Smoky Mountains to the Grand Canyon, major parks are grappling with vandalism, theft of resources and other misbehavior.