The so-called Monolith found in the Utah desert recently has disappeared. Either stolen by someone who thought it might be worth enough to justify the effort to remove it, or the original owner has reclaimed it. However, given the much-noted similarity to the centerpiece of the film 2001: A Space Odyssey and its sequel, suddenly vanishing is probably the most appropriate thing the monolith could do.
A quick recap for those living under a rock (instead of next to one) for the last week. A helicopter crew from the Utah Department of Public Safety (DPS) were counting bighorn sheep in the remote Utah desert when they spotted something odd. Investigation revealed an object resembling the mysterious monolith in Stanley Kubrick's 1968 masterpiece, planted in a location rather similar to that in which the object first appears.
Although the DPS deliberately kept the location secret, some very impressive sleuthing by people using the bighorn range, the geology of the area, and the helicopter's initial flight direction led to it being found on satellite photos. Despite the apparent remoteness of the site, some people were near enough to visit and take photos.

This weekend some of these visitors were disappointed, or perhaps delighted, to discover the monolith's absence.
The Utah Bureau of Land Management (BLM) posted a statement confirming that while carrying out a site visit on Saturday they discovered "an unknown party or parties removed the illegally installed structure referred to as the “monolith” sometime on the evening of Friday, Nov. 27.”
Riccardo Marino drove for 8 hours from his home in Colorado to see it, only to tell The Salt Lake Tribune he passed a truck with a large object on its back driving away from the site and the monolith gone on arrival.
The location had already become such a tourist attraction, Marino was just one of many to find their journey fruitless. Not everyone is sad about this, though. The remote location was originally kept secret in case people got lost or injured themselves trying to find the site. Since then there have been concerns some of the numerous pilgrims (some reportedly wearing ape suits) might damage the surrounding area. The BLM uploaded photos of nearby damage from cars adding a plaintive note requesting any visitors use the seven "Leave No TraceTM principles when visiting public lands,” something even the people who removed the monolith didn't manage, given the triangular base they left behind.
Most likely the market for artifacts of dubious legality will soon have a new entrant, but for those who like to cling to a little mystery, there is always this contribution from outstanding science writer Shannon Stirone:
Perhaps the Juno spacecraft could keep a lookout in Jovian orbit, just to be sure.