One of the top water officials in the West was pushed to resign by the Trump administration. Anne Castle served as a federal representative to the Upper Colorado River Commission.

Interior Secretary Doug Burgum has ordered federal officials to review and consider redrawing the boundaries of national monuments created under previous presidents to protect unique landscapes and cultural resources.

All kinds of animals use conspicuous colors. Research from biologists at the University of Arizona found it's a quirk of evolution that started around 150 million years ago.

The number of monarch butterflies spending the winter in western states like Arizona and California dropped dramatically even as federal officials move to extend protections for the pollinator.

A federal grand jury has indicted a Navajo man, his father and a business partner on charges that they were running illegal marijuana growing operations in New Mexico and on the Navajo Nation to supply the black market.

Solar advocates continue to fight what they call a “discriminatory” fee added to the utility bills of Arizona Public Service customers who have solar panels.

NPR's Ayesha Rascoe asks Dr. Rebecca Smith-Bindman about her research indicating CT scans, which emit radiation, will cause some 100,000 cases of cancer annually.

Matthew Bunn, a professor specializing in nuclear arms control at Harvard's Kennedy School, tells NPR's Ayesha Rascoe about concerns over a new nuclear arms race as the U.S. looks increasingly inward.

The Trump administration is pushing the boundaries of executive power, often by claiming emergencies.

HIV medications were supposed to be exempt from U.S. aid cuts. In Zambia, for example, those on the ground say otherwise.

The 88-year-old prelate appeared on the loggia of St Peter's Basilica and toured through St Peter's Square in the Popemobile.