A mysterious monolith made of ginger cookies was unveiled at Corona Heights Park in the American city of San Francisco on Christmas day. It is unclear who is behind the object, which shows three of the most used words of 2020 - home cooking, mysterious structures and the name of the place "Corona" - and unlike other times, this time it was composed of one of the traditional Christmas cakes, gingerbread or gingerbread cookies (and appeared on Christmas day).

"I was shocked to see the biscuit monolith for the first time," Josh Ackerman told the BBC.

Other monoliths have appeared around the world in recent weeks. The first, a mysterious metal pillar, was discovered in the desert in the US state of Utah last month - before disappearing a week later.

Close-up photo of ginger monolith

The internal structure of the gingerbread monolith is unclear.

Ackerman, who posted the photos from the site on Twitter, said he had seen a post on social media about the biscuit structure before going to see it up close on Christmas morning, but did not believe the news.

"So when I ran into the Corona Heights and saw that it was really there, it was very surprising," he told the BBC.

As with the other monoliths, the origin of the latter is not yet known.