There are routes sold as an adventure that end up being a stroll with a car park 200 metres away. This is not one of them. An hour's walk through oak forest, half an hour descending steps and an hour and a half paddling back across open sea - all of it a loop, starting and finishing at the same point.

The destination is the Faro del Caballo, a lighthouse in such an odd position and with such difficult access that it used to see only a handful of visitors a month. Today so many people attempt it daily that an online booking system has been introduced, capped at 100 visitors every two hours. Another example of a quiet place surviving only once it becomes popular enough that it has to be defended from its own audience.

763 steps down, not one back up

You set off from the coast towards the San Martin fort, one of six fortifications around Mount Buciero. The trail is marked in blue and easy to follow. After half an hour of steady, gentle climbing, the forest suddenly opens and a viewpoint appears looking towards El Fraile - a white limestone rock rising out of emerald water, sharp and so bright it recalls the cliffs off Capri.

Another half hour on comes the sign warning that 763 steps are next. That is one staircase with that many steps, built in the late 19th century by prisoners from the local penitentiary so that people could descend the cliffs to the ledge where the lighthouse stands. Before that, the only way here was by boat. Holding the steel cable that serves as a handrail and stopping fairly often to let those climbing up pass, you reach the lighthouse - decommissioned in 1993 - in another thirty minutes.

The way back is part of the story

Down below the scene is a mixture of everything: hikers crossing themselves at the thought of climbing back up those same steps, young people jumping into the sea from a height, tourist boats, sailing yachts, dinghies and kayaks. The wisest go back with a paddle.

The moment you are in the water, four strokes and a look back explain why the lighthouse is called Caballo - the horse shape the rocky ledge takes in profile. Right after it a cavity opens that the sea has carved at the foot of the cliff, so large that ships used to shelter inside it. It looks more like a cathedral than a cave, with two portals and vaults full of limestone formations.

The next stop is snorkelling in water only five metres deep, home to octopus, sardines and anchovies - the same ones caught in spring, salted by hand and kept in olive oil. The whole tour takes three hours, four with stops. If dolphins turn up - four and a half.

This is not a destination for an Instagram photo taken from the car park. It is a day that demands legs, arms and a little courage. Would we let a trail like this stay hard here, instead of building it a lift and a ticket office?