Utah Monolith Disappears

Remember thatmysterious monolithfound in the Utah desert last week? It's gone.

Public safety officers in Utah were assisting Wildlife Resources earlier this month in counting bighorn sheep, as part of the state's management efforts. And then helicopter pilot Bret Hutchings spotted it -- a 10-foot-high rectangular column just sitting there.

Now it's disappeared, replaced by a cairn -- a stack of rocks piled up to memorialize someone or something. Authorities have no idea who put it there or took it away. State officials say any investigation would fall to the local sheriff. (NBC News)