Healy's Mortar: A Weapon Carved from the Rock

Among the most fascinating remnants at the battery is Healy's Mortar, an extraordinary experiment from 1771. Rather than being cast in metal, this weapon was literally bored out of the solid limestone cliff face. Lieutenant Thomas Desaguliers Healy formed a flat surface at 45 degrees of elevation on a rock roughly 200 yards above sea level, then drilled a central shaft four feet deep. A three-foot-diameter circle was excavated by boring inclined holes all around, chipping away the partitions until a true parabolic chamber emerged.↗

On 14 May 1771, under the authority of General Lord Cornwallis, Governor of Gibraltar, the mortar was test-fired with 1,470 stones and a 27-pound powder charge. The discharge scattered rocks over 100 yards in all directions. While often described as a failure — many stones fell inside the fortress walls — the weapon was actually designed to blanket the landing beach below with lethal shrapnel, covering the very point where the British had breached the walls to capture Gibraltar in 1704. The floating batteries of the Great Siege in 1782 rendered it irrelevant, and Healy's Mortar was never fired in anger.↗

Visitors to the Apes' Den can still see the large hole bored into the rock face, a tangible reminder of this bold engineering experiment and the constant military ingenuity that shaped Gibraltar's defences over centuries.↗

The Legends of the Macaques

The presence of Barbary macaques on the Rock is steeped in folklore. One legend holds that they travelled from Morocco through a subterranean tunnel starting at St Michael's Cave and running beneath the Strait of Gibraltar. Another, far more consequential in the public imagination, claims that if the macaques ever leave, so too will the British.↗

This legend took on real urgency during World War II when numbers dwindled alarmingly. Winston Churchill himself took a personal interest, and additional animals were imported from North Africa to ensure the troop survived. Today the colony thrives across multiple packs on the steep limestone slopes.↗↗

Views Across Two Continents

The Apes' Den area is perched high enough on the Rock to deliver sweeping panoramic views across the Strait of Gibraltar, the Bay of Gibraltar, the Spanish coast, and the Atlas Mountains of North Africa on clear days. The open terrace-like setting, framed by the old fortifications and scrub-covered limestone, creates one of the most photogenic vantage points on the Upper Rock.↗↗

It can be a little disorienting to arrive expecting a cave or enclosed den — the name notwithstanding, the site is really an open area where the monkeys have decided to make their home, with the old military structures and the rock itself providing the backdrop.↗

Getting There and Visiting

The easiest way to reach Prince Ferdinand's Battery and the Apes' Den is via the Gibraltar Cable Car, which stops at the Middle Station right at the site. Between April and October, the Middle Station is not in service, so visitors must instead walk along Old Queen's Road from St Michael's Cave or from the Top Station. The walk is scenic but involves elevation, so wear sturdy shoes and plan accordingly.↗

Entry to the Apes' Den and all Upper Rock attractions is included with the Nature Reserve ticket. Adults cost £30 and children aged 5–11 cost £22; under-5s enter free. The reserve is not accessible by private vehicle for visitors — parking is available near the Jews' Gate entrance, and a shuttle option can be arranged at the Marketplace Bus Station.↗↗

Opening hours vary by season: 09:00–18:15 (last entry 17:45) from 1 October to 30 April, and 09:30–19:15 (last entry 18:45) from 1 May to 30 September. Your ticket is valid for the full day, so you can explore at your own pace.↗

Being Safe Around the Macaques

The macaques at the Apes' Den are remarkably habituated to people and can appear almost tame — juveniles especially may climb onto visitors or investigate bags with bold curiosity. They are, however, wild animals capable of biting and scratching, and touching or interfering with them is a criminal offence in Gibraltar.↗

Keep food and bags out of sight, avoid making sudden movements or loud noises, and do not approach between an adult and a baby. If a macaque shows you a pouted mouth (the Round Mouth Threat), step back calmly and give it space. The guiding principle is simple: observe, photograph, and respect their semi-wild freedom.↗↗