The National Park Service celebrates its centennial in August, so we asked NPS director Jonathan Jarvis to name six lesser-known national parks to consider for a last-minute summer vacation.

1) North Cascades National Park, Washington

"The North Cascades are one of the most biologically diverse parks in the U.S. Hike the Pacific Crest Trail in summer and if you listen closely you can imagine that Julie Andrews is signing 'the hills are alive.'"

2) Wrangell–St. Elias National Park and Preserve, Alaska

"The largest national park, it's bigger than Switzerland, and feels like you're coming out of the Ice Age, with bears and wolves dominating the landscape."

3) Craters of the Moon National Monument and Preserve, Idaho

"Roughly the size of Rhode Island, the miles of black lava and the remote location gives Craters a wonderful night sky that attracts amateur astronomers to view the heavens."

4) Guadalupe Mountains National Park, Texas

"Climb the five-mile trail up Guadalupe Peak to the highest point in Texas—at night you'll see more than 11,000 stars. Just watch out for scorpions!"

Check out more of the country's best national parks to head to right now.