SALT LAKE CITY (AP) — Deep in the Mars-like landscape of Utah's red-rock desert lies a mystery: A gleaming metal monolith in one of the most remote parts of the state.

The smooth, tall structure was found during a helicopter survey of bighorn sheep in southeastern Utah, officials said Monday.

A crew from the Utah Department of Public Safety and Division of Wildlife Resources spotted the gleaming object from the air Nov. 18 and landed to check it out during a break from their work.

They found the three-sided stainless-steel object is about as tall as two men put together. But they discovered no...