The Utah monolith was a hollow triangular metal prism about 9.5 feet tall, secretly installed on public land in a remote sandstone slot canyon in Lockhart Basin sometime between July and October 2016. It went unnoticed for more than four years until wildlife officials spotted it from a helicopter on November 18, 2020. Public fascination quickly drew visitors to the difficult-to-reach site, bringing environmental damage and concern for archaeological and Native American resources. Removed on November 27, 2020, by four Moab residents, it remained of unknown origin and purpose as of 2026. Its sudden appearance and disappearance made it a global curiosity that inspired many copycats.