There are multiple entry portals leading to underground structures on Mars, according to various ufologists and specialists. Are they human settlements or alien complexes?
The photographs below are from the Curiosity rover.
As you can see, these “doors” are easily identifiable and appear to be entry points to unknown installations.
One of these structures might be the weird anomaly that the Curiosity rover discovered a while ago. On the backdrop of one of the photographs, an item that looked like a dome could be seen.
There are stories that there are openings or windows beneath that dome. Extraterrestrial artifacts or portals to a subterranean base, perhaps?
Another entryway to a probable extraterrestrial facility on Mars may be seen in the video below.