Isabel II Fortress / Mola Fortress

The size is the thing. Walls, gates and gun positions run on across the whole headland, and a walk round takes two to three hours. The engineering carries the same weight — the volume of stone cut and moved into position out here in the 19th century. Then the paradox: a fortress built to be impregnable that was never attacked and never fired a shot in anger.

From the ramparts the view runs across the mouth of Maó harbour and out to open sea. A map comes with the ticket and audio guides are available, which helps, because the site is large enough to wander without ever finding the half of it.

• Time Allow two to three hours. It is all on foot, and the fortress covers the whole headland.
• Water No drinking water at the fortress or nearby — bring a bottle, because the walk round is in full sun.
• Footwear Gravel tracks and stairs throughout, so walking shoes or trainers.
• Buggies Electric buggies are for hire, and the hire is not cheap; stairs still cut off parts of the site.
• At the entrance Ticket desk, shop and audio guides, with toilets about 270 m away.

The Carretera de la Mola runs out to the end of the headland and finishes at the fortress, so the driving is the easy part. A gravel car park sits about 90 m from the site, with a second gravel car park about 733 m away in a straight line, and an information board stands by the entrance.

Public transport stops well short: the nearest bus stops are about 1.9 km and 2.3 km off in a straight line, which leaves the last stretch to be covered some other way. Everything inside the gate is on foot too, over gravel and up and down stairs, and the circuit takes two to three hours. Electric buggies are for hire for anyone who cannot manage that, though stairs still block parts of the fortress.

Best: the first hours after opening, or late afternoon, when the heat has gone out of the day and the light comes in low across the harbour.

Avoid: the middle of a summer day, and any arrival close to closing time.

The circuit is two to three hours over open ground with little shade and no water on site, which is what makes midday hard work out here. Leave yourself the full two to three hours before the gates shut, or you will be turning back halfway. August is the busiest month on the island.