The Knights Templar was one of the most important Catholic military orders in history. The rise to power of the Templars and their eventual downfall is the subject of many studies, legends, and conspiracy theories. Their mark on history remains fascinating. For a new documentary,

National Geographic’s Dr. Albert Lin took the latest archaeological tech to Israel to investigate one of the most important Templar sites and see if there’s anything new we can learn.

The Templars’ history is tied to the Holy Land and the Crusades, so it is not surprising that the documentary is set in the city of Acre, a port in modern-day Israel. This was the base of operations of the fabled knights after their headquarters in Jerusalem was lost when Saladin conquered the city in 1187.

Even in the late 20th century, crusader structures were still being discovered in the Levant, the most notable of which was the 350 meters (985 feet) “Templar tunnel” running underneath the modern city of Acre. These discoveries continue to shed light on this fascinating period of Middle Eastern history.

The Templar Tunnel is an underground passageway located in the city of Acre, in what is now Israel. This tunnel was built by the Knights Templar when the city was under the rule of the Kingdom of Jerusalem and served as a strategic passageway connecting the Templar palace to the port.

After Acre fell to the Mamluks during the 13 th century, the Templar Tunnel was lost and forgotten. It was only in 1994 that the tunnel was rediscovered by a woman battling a pesky blocked sewage pipe beneath her house.

The Kingdom of Jerusalem was established in 1099 following the conquest of Jerusalem by the participants of the First Crusade. About two decades later, the Poor Fellow-Soldiers of Christ and of the Temple of Solomon (known simply as the Templars) was founded by the French knight Hugues de Payens. This military order had its headquarters on the Temple Mount, and its main task was to protect Christian pilgrims who were traveling to the Holy Land.

Jerusalem was re-captured by the Muslims under Saladin in 1187 and the Templars effectively lost their headquarters. Although much of the Kingdom of Jerusalem had been overrun by the Muslims, the city of Tyre, along with a few isolated Crusader fortresses, continued to resist. In 1189, Guy de Lusignan, the king of Jerusalem, launched the first significant counter-attack against Saladin by marching against Acre.

Despite the small size of his army Guy was able to put the city under siege. Saladin was not able to muster his forces in time to crush the besiegers, who were soon reinforced by participants of the Third Crusade from Europe.

Remains of the ancient harbor of Acre. Moreno Soppelsa
Ever fearful of a renewed attack by Saladin and his successors, the Templars set about constructing an impressive fortress at Acre. The settlement was already well protected by high walls and the surrounding sea, but the new Christian occupants proceeded to construct seemingly impenetrable defenses.

According to Jones, Acre was a strategically significant Mediterranean port and controlling it was key to controlling access to the rest of the region. However, this meant that it was constantly under threat, both from enemies outside its walls and from infighting amongst those within.

This may explain why the Templars decided to construct a secret underground tunnel, leading from the fortress to the port. This would ensure a quick, easy escape for any inhabitants in case the city was overthrown and could provide a useful, secret channel for supplies if the city was besieged.

The Templar fortress marks the western end of the Templar Tunnel. This fortress is no longer in existence and the most noticeable monument in the area is the modern lighthouse. The western end of this tunnel is situated close to this lighthouse. The Templar Tunnel is 150 meters (492 feet) in length and crossed the city’s Pisan quarter.

The tunnel was carved into the natural stone as a semi-barreled arch and its ceiling is supported by a layer of hewn stones. The eastern end of the tunnel is located in Acre’s southeastern sector, in an area that once was the internal anchorage of the city’s port.

Today, this is the site of the Khan al-Umdan (meaning ‘Caravanserai of the Pillars’), which was constructed in the 18 th century when the city was under Ottoman rule.

However, in 1994, over 700 years after the fall of the fortress, a startling discovery was made by a woman living in the modern city of Acre. When she sent a local plumber to investigate the cause of her blocked drains, he stumbled into a medieval tunnel running right underneath her house.

Further excavations revealed that the tunnel had been constructed in the Crusader period, and ran all the way from the fortress to the port. This was an extremely significant discovery, as it’s one of the rare pieces of Crusader architecture in Acre to have survived the invasion of the Mamluks.

The team uncovered tunnels sprawling underneath the city as well as a guardhouse, showing how the Templars may have moved their treasures from the port to their treasure tower. What remains of the tower, however, is buried under dirt and rock. Currently, though, there is no plan to excavate any of this as we have no confirmation the Templars’ treasure is actually there.

When France’s King Philip IV took power, the royal family was deeply indebted to the Templars, but the king decided he didn’t have to pay back anything if there was no order.

Rumors spread about the knights’ eroding public trust and without this support the king arrested and tortured members of the order, producing false confessions for the benefit of Pope Clement V, who officially disbanded the Knights Templar in 1312.