Cliff trail

Setting off from Gros, just before the end of Zurriola beach, the Corazón de María church marks the start of the climb to Ulia, right at its junction with the petrol station. The ascent is steep and a little rough at first, but the route soon reaches a level tarmac lane. Before long we come to a viewpoint which, when the vegetation allows, offers excellent views over the city. We carry on into a wood.

About 200 m after the viewpoint we find a small turning on the left: we take this narrow path, leaving the main track, which continues on to the Ulia picnic area.

This narrow path keeps climbing steeply and, once we've tackled this tough slope, we reach a high, open area called "Kutralla gaina", where the panorama changes completely. Here we look out over the first cliffs of Ulia, home to a large colony of gulls. Our route continues on the level and climbs gently to skirt the sheer cliff that plunges dizzyingly into the sea.

From Kutralla we follow the path downhill. After passing the old washhouse, we take the left fork. Little by little the path becomes a stone causeway leading to the viewpoint overlooking Monpás point. Soon the wood opens up and we spot Animeta point and the Atalaundi rocks. On clear days you can see not only Biarritz but the coast of Les Landes too. Heather, ferns and gorse are the usual plants here, dotted with pines and Pyrenean oaks.

Above Animeta point we reach another crossroads. One path climbs to the summit of Ulia, while another drops down to the Atalaundi rocks or continues along the coastal path. We take the path going down. From here the trail becomes a constant up-and-down that ends at the Casa del Emisario, next to the water outfall. We take the concrete track uphill and pick up the mid-slope path again on the way to Pasaia.

Before reaching Mendiola bay we take a left fork and begin the descent. At Mendiola the path reveals another side of Ulia: the water paths. Here it can be tricky to find the way: at one point the path splits into three – one goes down, one goes up and a third, harder to spot, continues along the mid-slope – and it's this last one we need to take. We reach a narrow tunnel 200 m long that we have to walk through, followed by two aqueducts.

The second aqueduct brings us to the most impressive stretch of cliffs on the whole route, right up against the sheer sandstone walls. Pushing on through the ferns, we head for the La Plata lighthouse, perched on an almost vertical cliff 163 m above the sea. The lighthouse takes its name from the silvery (plata) colour its slabs turn when battered by the waves.

From the lighthouse, the access road brings us closer to Pasaia. After about 300 m we take a path on the left leading to the Senokozuloa steps, which drop down to the mouth of the bay. Ulia was once a single mountain together with Jaizkibel, Urgull and Santa Clara island, and the Pasaia estuary is one of the breaches the water has carved through this coastal range. Following the shoreline we soon reach Albaola, the Basque Maritime Factory, where a replica of the San Juan whaling ship is being built.

Arriving in San Pedro, Victor Hugo's words about this place come to mind: a row of narrow houses packed tightly together, painted white, saffron and green, with big balconies and, at their feet, the sea. Once the walk is over, you can take the motorboat across the bay to visit San Juan, a small, picturesque fishing village opposite San Pedro.

To get back to Donostia, the bus is your best bet: at the first roundabout in San Pedro, take the E9 line, which drops you back in Gros at the very spot where the climb to Ulia began.