The sandstone formations known as, from left: the West and East Mitten buttes and Merrick Butte at Monument Valley, in the Navajo Nation, Ariz., Oct. 6, 2025. Fallout from the slump in travel to the U.S. has reached all the way to Monument Valley, where a dozen Navajo guides told The New York Times that their international business evaporated this year. (Gabe Castro-Root/The New York Times) By GABE CASTRO-ROOT The red sandstone buttes and rugged expanses of Monument Valley, in the Navajo...