NASA has spotted mysterious 'spiderwebs' on a never-before-explored region near the equator of Mars.

The agency's Curiosity rover has been dispatched to probe these bizarre structures — which cover a six to 12 mile stretch of Martian desert — as the machine searches for signs that this long desolate world once supported alien life.

Geologists suspect that the spiderwebs are a gigantic version of a type of crystalized minerals, known as a 'boxwork,' which appear inside some caves on Earth. 

They can be found on the ceiling of Wind Cave in South Dakota, which were created by calcium carbonate mineral water seeping into cracks between softer rocks that hardened into crystals.

But the sprawling, over 3,800-acre-wide boxwork on Mars differs in that it was likely formed by Martian seawater and may have trapped fossils of ancient life in its web.

'These ridges will include minerals that crystallized underground, where it would have been warmer,' according to Rice University geologist Dr Kirsten Siebach. 

'Early Earth microbes could have survived in a similar environment,' Dr Siebach explained, nothing that the 'salty liquid water' that created these Martian webs an ideal location to find lingering fossil evidence of ancient alien microbes.

To read more, click here.