NASA’s Curiosity rover is ready to move out of the valley of Gediz Vallis and travel slow and steady for a month to a fascinating new area of great interest on Mount Sharp, a 5-kilometer (3-mile) tall mountain at the center of Gale crater. The new area has been called the boxwork, and views from orbit show it to have a web-like structure.

It was not a Shelob-like creature that spun this intricate web – scientists believe that it was the water on Mars’ last hurrah in the region that carved the complex pattern. As the Red Planet was transitioning from a wet world into the dry one of today, some of the water flowing off Mount Sharp carried minerals that settled into fractures in the surface rock and subsequently hardened.

Over eons, the relentless action of the thin Martian atmosphere eroded some of the rock away, revealing the hard minerals that had cemented in the fractures, giving this beautiful spider web-like pattern.

There are boxwork structures on Earth too in cliffsides and caves, but they are different. Firstly, on Mars, they formed as  water was disappearing. Secondly, they are enormous, spanning an area of 10 to 20 kilometers (6 to 12 miles) – and it might be an intriguing place for Curiosity to look for traces of ancient life.

“These ridges will include minerals that crystallized underground, where it would have been warmer, with salty liquid water flowing through,” said Kirsten Siebach of Rice University in Houston, a Curiosity scientist studying the region. “Early Earth microbes could have survived in a similar environment. That makes this an exciting place to explore.”

This is not the only spider-related feature on the Martian surface. At the South Pole, there are the “spiders on Mars” – unrelated to Bowie’s band – related to the current freezing and sublimation of ice rather than ancient water as researchers have found recently.