Theories abound over mystery metal monolith found in Utah

Structure compared to monolith featured in 2001: A Space Odyssey - and could it be the work of sculptor John McCracken?

A giant, metal mystery slab has captured the attention of millions, as people speculate over how such a structure came to be in a remote part of southern Utah.

The object was first spotted last week by a helicopter pilot and wildlife officers who were flying above the rugged area to conduct an annual count of bighorn sheep for the state. It immediately drew comparisons to the monolith featured in 2001: A Space Odyssey as well as inviting suggestions it could be the work of extraterrestrials.