By Brooke Porter Katz
April 18, 2014

Tomorrow marks the start of National Park Week (April 19-27), and to celebrate, the country’s 400-plus parks are waiving entrance fees all weekend long. It’s a big year for the National Park Service, with milestone anniversaries (Yosemite turns 150 this year; Rocky Mountain National Park is 100) and important developments (including major renovations to Yellowstone’s oldest hotel).

Heading to the Grand Canyon? Make sure to check out Hermits Rest and Lookout Studio, two buildings by architect Mary Jane Colter that turn 100 this year. Death Valley National Park—celebrating its 20th anniversary—is currently awash in an unexpected amount of wildflowers, while New River Gorge National River and Gauley River National Recreation Area, both in West Virginia, are having better-than-ever whitewater rafting, thanks to mountain run-off from an especially harsh winter.

Many parks are offering special events and promotions throughout the week. Olympic National Forest’s Lake Quinault Lodge, in Washington, is giving guests a chance to help restore hiking trails on Earth Day (April 22). And Wyoming’s Togwotee Mountain Lodge, with access to both Grand Teton and Yellowstone, is running a sweepstakes on its Facebook page; the winner receives a two-night stay plus a horseback-riding excursion this summer.

The National Park Foundation is also using the week as a way to give back, through a partnership with Walt Disney Studios and its new film Bears. For every ticket purchased between today and April 24, the indie film label Disneynature will make a donation to the foundation to support wildlife in America’s national park.

Brooke Porter Katz is an Associate Editor at Travel + Leisure. Follow her on Twitter at @brookeporter1.