The road leaves the Tabernas desert floor and runs alongside the A-92 without ever joining it, so the opening kilometres are gentle and fully exposed before the real climbing starts at Gérgal. From there it is roughly 23 km and about 1,390 m of ascent at around 6%, a long grind that sits near 7% for kilometre after kilometre with pitches into double figures and a steepest kilometre of about 11%. Aulago, some 8 km up, is the only real sign of life and the last place to fill bottles, because there is nothing above it. Young pine forest takes over through the middle of the climb and gives some shade, then thins out above 2,000 m and leaves bare, scrubby ground and long views back over the province. The final stretch steepens again into switchbacks before the top at 2,168 m, where half a dozen huge white domes of the Calar Alto observatory sit on the ridge. The surface is good and traffic is light, but there is no café and no water at the summit: the nearest food is back down in Gérgal, or the petrol station near the foot of the climb.