The Pyrenees are significant to Jane Eyre because of their symbolism when they are referenced in the text. Brontë writes "I rave: perhaps at this moment he is watching the sun rise over the Pyrenees, or on the tideless sea of the South" (Brontë 377). In this moment, Jane is heading towards Thornfield to reunite with Rochester. She is not yet aware of his accident and theorizes that he has gone abroad. This quote explains how Jane is scared that Rochester may have forgotten her and gone on to live a life of adventure without her. Additionally, Brontë was most likely referencing peak Aneto specifically because, according to iloveski.org, "The first documented ascent of Aneto was made on 20 July 1842" and "this expedition undoubtedly marked the beginning of a fascination with the highest peak in the Pyrenees". That historic ascent happened just a few years before Brontë wrote Jane Eyre. That means that there is a chance Brontë heard about it when she heard about the Pyrenees mountain range. It is further emphasized by the fact that, according to iloveski.org, "The Aneto, with its imposing 3,404 metres, is the highest mountain in the Pyrenees and the second highest peak in Spain". That fact implies that Jane thinks Rochester would have gone on to live a life so adventurous without Jane, he would have left in a year to climb the second highest mountain in Spain. It shows how much she is worried that he lacks care for her and what her view of his adventurous lifestyle is.
This information comes from Jane Eyre by Charlotte Brontë (book) and iloveski.org (website). The picture comes from picryl.com.
This location illustrates gothic convention because of the remote setting and menacing mood. The mountain itself looks ominous (as seen in the picture). It exudes a sense of danger. It's icy and grey, with a flat cliff face leading up to its peak. It looks desolate and intimidating. That sets the mood of the book within that of gothic convention.
Mapping this location on COVE reveals how the novel's real geography grounds its Gothic atmosphere. The image of the peak shows how it's a (difficult) vertical climb to the top, reflecting the challenges Rochester had to face in Jane's absence (the fire). The look of the Pyrenees mountains mirrors the hopeless mood of Jane and Rochester's struggles while they were separate.
Image: https://picryl.com/media/pico-aneto-mountain-nature-landscapes-396b86