I don’t know why the smooth golden dome of this summit has taunted me ever since I spotted it on the horizon of Pyrenean peaks in the Ariège. Its distinctive profile seemed to pop up everywhere I went. Rising up smoothly on one side, the dome breaks off abruptly where its eastern side has been chiselled away, no doubt by long-ago ice action. I’ve wanted to stand on that summit for years, although I’d turned back twice. This October, seeing a window of clear, cool days, I was going to do it.