Portugal, land of sun, sea and fine wines, has ancient secrets and natural wonders under its feet that few people know about. Beneath the surface, a network of caves, mysterious wells, and Roman galleries are just waiting to be discovered. Come with us on a journey through some of Portugal’s most fascinating underground treasures.

1. The Mira d’Aire Caves

In the heart of Portugal, near the small town of Mira d’Aire, lie some of the largest and most impressive caves in the country. Discovered in 1947, the Mira d’Aire Caves extend for more than 11 kilometers, although only a small part is accessible to the public.

As we descend the steep stairs, the cool, humid air envelops us, and the soft lights reveal stalactites and stalagmites that look like otherworldly sculptures. Your imagination may run wild as you contemplate the bizarre and intriguing shapes sculpted by the water over thousands of years. The main chamber, known as the Great Hall, is a cavernous hall that evokes a natural cathedral, where the grandeur of nature is displayed in all its splendor.

2. Quinta da Regaleira Initiation Well

In Sintra, a land of palaces and lush gardens, there is a well that seems to be straight out of a Gothic fairy tale. The Initiation Well at Quinta da Regaleira, with its nine levels symbolizing the nine circles of Dante’s inferno, is a place shrouded in mystery and symbolism.

As you descend the spiral staircase, each step takes you deeper into an introspective journey. The stone walls, covered in moss, and the openings that let in soft light create an almost supernatural atmosphere. At the bottom of the well, a mosaic of a Templar cross marks the end of the descent and the beginning of a new understanding.

3. Lisbon’s Roman Galleries

Beneath the bustling streets of downtown Lisbon lie Roman galleries that have remained forgotten for centuries! Discovered accidentally after the 1755 earthquake, these underground structures are a window into the city’s Roman past.

Every year, for a few days in April and September, the galleries are opened to the public, allowing a rare opportunity to explore this labyrinth of tunnels and arches. Walking through these narrow passages, lit only by lanterns, is like traveling back in time. The cold stone underfoot and the feeling of confinement increase the connection with the ancient Romans who once walked here.

4. Alvados Caves

Not far from the Mira d’Aire Caves, the Alvados Caves offer an equally impressive experience. Known for their natural beauty and unique formations, these caves are a hidden treasure in the Serra de Aire.

The journey through the caves reveals a symphony of shapes and colors, where the stalactites hang like swords of Damocles and the stalagmites stand like silent sentinels. The dripping water creates a hypnotic rhythm that echoes through the chambers.

5. Loulé Rock Salt Mine

One of the most fascinating underground attractions in the Algarve is the Loulé Rock Salt Mine. This mine is still in operation and offers guided tours that descend to more than 230 meters below the surface. The sensation of descending into the underground world is overwhelming, and the magnitude of the mining operation is impressive.

The salt galleries, illuminated by artificial lights, create a surreal atmosphere. The bright white walls reflect the light, transforming the mine into a kind of ice cave. The silence here is almost palpable, which is interrupted only by the occasional sound of machines at work.

6. Algar do Carvão

In the Azores, Algar do Carvão is a geological rarity: a volcanic chimney accessible to the public. Located on the island of Terceira, this fascinating place offers a unique view of the interior of a dormant volcano.

The descent into Algar do Carvão is a journey into the heart of the earth. The volcanic walls, covered in lush vegetation, create an almost primordial atmosphere. At the bottom, an underground lake reflects the irregular walls, which creates a spectacle of light and shadow.

7. Santo António Caves

Near Porto de Mós, the Santo António Caves are another example of Portugal’s intriguing underground world. Discovered in 1955, these caves are known for their impressive limestone formations and the clarity of the underground water.

Walking through the caves is like exploring an underground palace. The wide chambers and winding passages are adorned with delicate stalactites and imposing stalagmites. The soft lighting highlights the natural beauty of the formations and turns the visit into an almost magical experience.

8. Benagil Cave

On the picturesque coastline of the Algarve, near Lagos, lies one of Portugal’s most iconic natural formations: the Benagil Cave. Only accessible by sea, this cave hides a golden sandy beach and is famous for its opening in the ceiling, which lets in sunlight, creating a stunning natural spectacle.

Paddling into Benagil Cave is an experience in itself. As you approach the entrance to the cave, the sound of the waves reverberates off the rocky walls, amplifying the sense of mystery. Inside, the sunlight penetrating through the ceiling illuminates the turquoise water and golden sand, creating an almost ethereal atmosphere. It’s a place where nature seems to have decided to carve out a piece of hidden paradise, waiting to be discovered by those willing to venture out.

9. Moeda Caves

Located near Fátima, the Moeda Caves are another underground wonder worth visiting. Discovered in 1971 by two hunters, these caves offer a spectacle of limestone formations that seem straight out of a work of art.

The guided tour of the caves takes us along a 350-meter path, where stalactites and stalagmites compete for our attention. The main chamber, known as the Crib Room, is particularly impressive, with formations reminiscent of biblical figures. The combination of artificial lights and natural forms creates a magical atmosphere, each corner revealing a new surprise.

10. Castromil Gold Mine

In the north of Portugal, near Paredes, we find the Castromil Gold Mine. These ancient mines were exploited by the Romans and later during the gold rush of the 19th and 20th centuries. Today, they are a fascinating testimony to the history of gold mining in Portugal.

A visit to the mines allows you to learn about the gold extraction techniques used over the centuries. The dark galleries and deep shafts create a sense of adventure, while the displays of old tools and mining remains transport us to a bygone era. Exploring these mines is a history lesson about the gold rush that once swept this region.

11. Escoural Caves

In the Alentejo region, the Escoural Caves are an important archaeological site that offers a glimpse into prehistoric life. Discovered in 1963, these caves contain cave paintings and animal bones dating back to the Upper Paleolithic.

Entering the caves is like entering a natural museum. The walls are covered with paintings of animals and human figures made over 20,000 years ago. The presence of bone remains and stone tools indicates that these caves were inhabited by hunter-gatherers, making them one of the most important archaeological sites in Portugal. The visit is an educational journey into humanity’s distant past.

Final Thoughts

Exploring Portugal’s underground world of caves, mines, and galleries offer unique adventures, each place representing a piece of Portugal’s vast underground puzzle. From the stunning Mira d’Aire Caves to Lisbon’s intriguing Roman galleries, Underground Portugal is a treasure waiting to be discovered. Venture out, explore and allow yourself to be captivated by the secrets hidden beneath your feet.