17. Bethel, New York
When the Woodstock Music Festival was about to open near Bethel, New York, the roadways became clogged for over 20 miles. More than 500,000 people tried to drive to the event from August 15 and 18, and those rural roads couldn’t take it. Many people simply abandoned their cars and walked to the festival, which only made matters worse. Things got so congested that some performers had to fly in by helicopter as they couldn’t get to the farm on the road.