O'Hara's Folly: The Tower Built to See Cadiz That Could Not

23 August 2026 Last checked 2026-08-23

A governor built a tower on Gibraltar's summit to spy on Cadiz. Cadiz was not visible. Lightning wrecked it, and in 1888 six shots finished it off.

Stand at the top of the Rock of Gibraltar, 426 metres above the sea, and you are standing on the site of one of the most expensive jokes in the territory's history. A governor built a tower here to watch the Spanish fleet at Cadiz. Cadiz could not be seen. Lightning then finished what geography had started, and a century later a gun crew knocked the ruin down to settle an argument.

That is the story the guides tell, and most of it holds up. Some of it does not. The tower was real, the failure was real, and the demolition in 1888 is a matter of record. But the ship usually named as the culprit had already sunk, twice over, and the dates people quote for the tower do not sit comfortably beside the dates of the man it is named after. Here is what actually happened, what is disputed, and how to stand on the spot yourself.

The governor who surrendered to Washington and to Napoleon

Charles O'Hara was born in Lisbon around 1740, the illegitimate son of an Irish peer, and he had one of the strangest careers in the British Army. At Yorktown in 1781 he carried out the surrender on behalf of Lord Cornwallis, who pleaded illness, which means O'Hara personally handed over a British army in front of George Washington. Twelve years later, at the siege of Toulon, he was wounded and taken prisoner by French troops commanded by a young artillery officer named Napoleon Bonaparte.

He spent nearly two years locked in the Luxembourg in Paris through the Terror, and was exchanged in 1795. Within months he was Governor of Gibraltar, a post he held from 30 December 1795 until his death in February 1802. The garrison called him the Old Cock of the Rock. He was theatrical, generous, famously hospitable, and by most accounts a genuinely effective governor at a dangerous moment for the fortress. He is also one of only two governors actually buried in Gibraltar, and his memorial is still in the King's Chapel.

A man who had surrendered a British army to Washington and then his own sword to Bonaparte was never going to be modest about what he built at the summit.

A tower built to see a city 60 miles away

O'Hara's idea was simple and, on paper, excellent. Gibraltar's problem in any war with Spain was intelligence. The Spanish fleet lay at Cadiz, and the first the garrison usually knew of a sortie was when sails appeared in the Strait. Put an observation tower on the very top of the Rock, O'Hara reasoned, and lookouts could watch the harbour at Cadiz directly and hand the garrison days of warning.

The tower was built of hewn stone and iron, and it was originally given the respectable name of St George's Tower. Cadiz sits about 60 miles away, roughly 97 kilometres, in a straight line up the Atlantic coast. That distance is the whole problem, and O'Hara appears to have been the only man on the Rock who did not see it coming.

Why it could never have worked

Two things defeat the plan, and either one on its own is fatal.

The first is the ground in between. The coast running north from Tarifa towards Cadiz is not flat. Hills and sierras rise between the Rock and the bay, and the harbour at Cadiz sits low and behind them. No amount of height at the Gibraltar end lifts a sightline over high ground standing in the way that far off.

The second is the curve of the earth. From 426 metres the geometric horizon in ordinary conditions falls somewhere around 74 kilometres. Cadiz at roughly 97 kilometres is well beyond it. Even across a perfectly flat sea with nothing at all in the way, the harbour would have been below the horizon and out of sight.

Add the Rock's own weather and it gets worse again. On easterly days the summit vanishes into the levanter cloud that forms over the ridge, which we explain in our guide to the Gibraltar levanter cloud. A lookout post on the top of the Rock spends a good many days of the year inside a cloud, watching nothing.

Lightning, and the name that stuck

Not long after it was finished, a violent storm drove a lightning bolt into the tower and wrecked it. Accounts hold that a sentinel on duty was killed. That detail is repeated almost everywhere and sourced almost nowhere, so treat it as garrison tradition rather than record, but the strike itself and the damage are reported consistently.

The garrison, who had watched the money go up the hill and the view fail to arrive, renamed the place with the economy soldiers reserve for their commanding officers. St George's Tower became O'Hara's Folly. The ruin stayed up there, unrepaired, for most of the nineteenth century, a landmark that meant the opposite of what its builder intended.

Where the story gets slippery

This is the part the guidebooks skip. Two details in the standard version do not survive a check.

The first is the date of construction. The most repeated version has the tower going up between 1787 and 1791, ordered by O'Hara as Lieutenant Governor. But O'Hara was not appointed Lieutenant Governor of Gibraltar until 1792, and did not become Governor until the end of 1795. Either those construction dates are wrong, or the tower predates his command and he only completed or enlarged it. The sources contradict one another and nobody appears to have reconciled them.

Six shots, and a ship that was not there

By 1888 the ruin was in the way. The army wanted the summit for a modern coastal battery, and the tower was scheduled for demolition. What happened next reaches us in two versions.

In the plainer account, the tower simply came down as a result of naval gunnery practice. In the better one, the gunners of the garrison and the officers of a Royal Navy ship laid a wager over whether the ship could hit the summit at all. The crew cranked their guns to an extreme elevation and brought the tower down with the sixth shot.

The ship is always named as HMS Wasp. That is where it falls apart. The Royal Navy had two gunboats of that name in this period, and neither was afloat in 1888. The Wasp launched in 1880 was wrecked on the rocks below the Tory Island lighthouse off Donegal in September 1884. Her successor, launched in 1886, was lost with all hands in the seas east of Singapore in October 1887, one of the Navy's more haunting disappearances.

So either the year is wrong, or the ship's name was garbled somewhere in the retelling, or the wager is a good story that attached itself to a routine demolition. The demolition happened. The ship, on the evidence, did not. It is worth saying plainly, because you will hear the Wasp named at the summit and in half the guidebooks on Main Street.

What stands on the summit now

O'Hara's Battery was built on the tower's footprint between 1888 and 1890, and it is still there. The first gun was a 6 inch breech loader on a Vavasseur mounting. That was replaced around the turn of the century by a 9.2 inch breech loading gun, and the mounting was upgraded again in the 1930s. The barrel still standing up there is the 9.2 inch, and the Ministry for Heritage listing records what is protected with it: the magazines, the engine room, the associated works and a spare barrel.

It is a serious weapon. The 9.2 inch had a range of about 29,000 yards, roughly 26 kilometres, which put the whole Strait and a slice of the North African coast inside its reach. The battery was manned through both world wars. Its guns, and those at Lord Airey's Battery further along the ridge, were fired for the last time on 7 April 1976 during a training shoot, shortly before coastal artillery was declared obsolete.

The site stayed closed to the public for decades. The Government of Gibraltar opened it in May 2010 and announced a reopening on 21 June 2023 after restoration work, although that release also said access to the gun platform itself would stay restricted until the works on the gun were finished. It is shut again now. The Nature Reserve's page for the battery says the site is undergoing refurbishment and is not open to the public, and in August 2026 plans to rebuild it as a full heritage attraction reached the Development and Planning Commission. Our guide to Gibraltar's highest point sets those documents out in full.

Getting to the top in 2026

One thing to plan around. The Gibraltar cable car closed on 18 November 2025 for a complete rebuild and is not expected to carry passengers again until 2027, so the quick ride to the upper station is not an option this year. Our Gibraltar cable car status guide tracks the works. The summit is still entirely reachable. It just takes a little more thought.

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The Mediterranean Steps are the way to do it if your legs allow. The path starts at Jews Gate, near the Pillars of Hercules monument, climbs the eastern face on cut stone stairs and switchbacks, and finishes at O'Hara's Battery. It runs a little under two kilometres with roughly 240 metres of ascent, and most people take between one and two hours. It is not technical, but it is exposed in places and it is genuinely hot in summer. Carry water and start early.

Admission to the Gibraltar Nature Reserve covers St Michael's Cave, the Skywalk, the Great Siege Tunnels and the rest of the upper sites. The reserve's plan your visit page still shows O'Hara's Battery among them, but the battery's own page says it is closed for refurbishment, so do not buy a ticket on the strength of the battery alone. The reserve ticket is £30 for an adult, £22 for a child aged 5 to 11, and free for children aged 0 to 4. The reserve runs 9.30am to 7pm from May to September and 9am to 6pm from October to April. Prices and hours do change, so check before you set out.

Private cars are not allowed at the battery itself, so however you get up the hill the last stretch is on foot. If you want a full day on the Upper Rock, our guide to the Rock of Gibraltar covers the other sites worth your time, and the Skywalk glass floor guide covers the viewing platform you will pass on the way.

Making a day of the summit

Done properly this is a full day. Start early, walk up, stand on the summit ridge and read the Strait from the highest ground in the territory, then drop down through the Skywalk and St Michael's Cave and be back in town by mid afternoon with your legs complaining. While the refurbishment lasts you will not be going inside the battery, so build the day around the climb and the view rather than around the gun. Crossing from Spain is straightforward now that routine passport checks at the land border ended on 15 July 2026, which our border changes guide explains in full, but a summit day still works far better if you sleep on the Rock and start at first light.

Victory Suites on Devils Tower Road is a practical base for exactly this kind of day. It is about a ten minute walk from Grand Casemates Square and minutes from Gibraltar International Airport, and our 100+ serviced apartments have full kitchens, so you can load up before a climb and cook something decent when you get back down. There is an indoor pool and a gym in the building. Message the team and they can tell you whether the levanter has swallowed the summit before you spend two hours walking up into it.