President Donald Trump's call to review 27 national monuments established by three former presidents put protections on large swaths of land in limbo, including areas with ancient cliff dwellings, towering sequoia trees, deep canyons and ocean habitats where seals, whales and sea turtles roam.
Trump and other critics say presidents have lost sight of the original purpose of the law created by President Theodore Roosevelt that was designed to protect particular historical or archaeological sites rather than wide expanses.
Interior Secretary Ryan Zinke made his first recommendation Monday, proposing to reduce the size of Bears Ears National Monument in Utah. He is expected to issue a final report in late August for all the monuments.
Here's a closer look at five of the 27 monuments that are being re-examined.