The monoliths that have recently appeared in Utah (L), Romania (C), and California (R).
  • Yet another monolith has been discovered. This time, it's in a Dutch nature reserve.
  • Walkers came across the metal pillar when walking in a Friesland park, Dutch paper Algemeen Dagblad reports.
  • People suspect that this is a prank, according to local media.
  • The first monolith to be discovered was in a Utah desert last month. Since then, others have appeared in Romania, California, and Pennsylvania.
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Monoliths are popping up all over the place.

The first grabbed the world's attention after it mysteriously appeared in a desert in Utah and, shortly after, was covertly removed.

Then, a mysterious metal pillar was spotted in Romania. It also promptly vanished.

Police then investigated an incident where a group of young men in California tore down yet another monolith and replaced it with a cross.

A fourth monolith was on display outside a candy shop in Pittsburgh, Pennsylvania. This one, however, was a marketing stunt.

Now, walkers in a northern province of the Netherlands have stumbled upon one more monolith.

On Sunday morning, a group of people on a morning stroll came across a towering metal structure in the heart of Kiekenberg nature reserve.

The monolith, near the village of Oudehorne, was covered in ice and surrounded by a small pool of water.

The walkers were baffled about how it got there because there were no visible footprints near it, reports the Dutch paper Algemeen Dagblad.

While some people have playfully toyed with the idea that the monoliths are proof of alien life, locals suspect it is a prank.

Hikers suspect it's a "New Year's eve stunt," according to Friesland broadcaster Omrop Fryslan.