Unknown antennas have appeared in the mountains around Salt Lake City, the capital of the U.S. state of Utah, and authorities do not know who installed them and for what purpose, Vice reports.

According to local residents, the strange antennas first began to be noticed about a year ago. It's a standard set of a fiberglass LoRa antenna, an enclosed battery and a solar panel to power it. Authorities have since found dozens of similar antennas of the same design.

Unauthorized placement of such structures is prohibited on public land. Authorities noted that the antennas were installed both in the mountains and on local university property.

According to Tyler Fonarow, Salt Lake City's hiking trails manager, the highest point at which one of the antennas was found was the summit of Mount Wire, which is over two thousand feet high. He explained that the trip to the site would take at least an hour, and to get to the antenna would require an additional difficult route to climb.

He also said that the antennas were unmarked and that they were screwed into rocks in the mountains.

According to the mainstream version online, the antennas are actually part of a Helium cryptocurrency mining operation. It is a type of cryptocurrency that uses antennas to create a global network and mine tokens. Online, Helium miners like to brag about the height of their antennas.