This summer is likely to bring bigger crowds, longer entry waits, closed trails, uncleaned toilets, uncollected trash and more at national parks. If you go, plan ahead to avoid headaches.

“ Find a national park and come visit!” the annual event’s webpage encourages, pointing to the 433 “parks” across the National Park System, including national battlefields, monuments and seashores – not just places with National Park in their name like Great Smoky Mountains or Yosemite .

Earth Day also falls during National Park Week. Celebrated for 55 years, one billion people in 193 countries host events and celebrations of the planet, its resources and our commitment to protect it. Many of our national parks will have special Earth Day demonstrations of earth science or discussions of the latest environmental concerns.