You descend in a slow spiral, round and round, the light from the opening above growing fainter with every turn. Moss clings to the stone balustrades, water drips somewhere below, and voices echo up the shaft. At the bottom, 27 metres underground, a compass rose is set into the floor, and a dark tunnel leads away into the rock. Follow it, and you'll emerge beside a lake, stepping from stone to stone across the water beneath a waterfall.

This is the Initiation Well, the most famous corner of Quinta da Regaleira, and one of the most magical places in Portugal. But the well is only the beginning. The whole estate, on the edge of Sintra's old town, is a puzzle built in stone, full of symbols, hidden passages and stories waiting to be decoded. Here's how to make the most of it.

The millionaire and the set designer

The estate takes its name from the Baroness of Regaleira, who owned it in the 19th century. In 1892 it was bought by António Augusto Carvalho Monteiro, a Portuguese collector born in Rio de Janeiro who had made an enormous fortune in Brazil, much of it from coffee and precious stones. He was so rich that the Portuguese nicknamed him 'Monteiro dos Milhões', Monteiro of the Millions.

Carvalho Monteiro was a passionate collector of books, coins, natural history specimens and anything connected with the poet Luís de Camões. He was also fascinated by philosophy, mysticism and secret traditions. To build his dream retreat, he hired the Italian architect Luigi Manini, who had worked as a set designer for the opera, including at Lisbon's São Carlos Theatre. That theatrical background is visible everywhere at Regaleira.

Most of the estate was built between about 1904 and 1910. After Carvalho Monteiro's death in 1920, it passed through several private owners, and in 1997 it was bought by the municipality of Sintra, which opened it to the public. It forms part of the Cultural Landscape of Sintra, a UNESCO World Heritage Site.

A garden full of symbols

Regaleira is often described as a garden of initiation. Its designers filled it with references to alchemy, the Knights Templar, the Rosicrucians, Freemasonry, classical mythology and Dante's Divine Comedy. Nobody knows exactly what Carvalho Monteiro believed, and part of the fun is spotting the symbols and making up your own mind. The general idea, many visitors believe, is a journey from darkness to light, from the underworld up to the heavens.

The Initiation Well

The Initiation Well was never meant to hold water. Instead, it is an inverted tower: a spiral staircase descending around a central shaft, with nine landings separated by flights of steps. The number nine is often linked to Dante's nine circles of Hell, or to the nine sections of Purgatory and Paradise. At the bottom, a compass rose sits over an eight-pointed cross, a symbol associated with the Knights Templar and the Order of Christ.

From the bottom, tunnels lead out through the rock. One path emerges at the Lake of the Waterfall, where you cross on stepping stones, while others lead to grottoes elsewhere in the garden. The tunnels are dark and damp, and part of the experience is finding your way.

The Unfinished Well and other secrets

Close by is a second, simpler well, known as the Unfinished Well, with a straight staircase spiralling around rough stone walls. Elsewhere in the garden, look for the Portal of the Guardians, a gateway flanked by towers that hides one of the entrances to the tunnel network; the Grotto of Leda, with its statue of Leda and the swan; and the Regaleira Tower, which you can climb for views over the estate and towards the Moorish Castle on the hill above.

The palace and the chapel

The palace itself, with its pinnacles, gargoyles and an octagonal tower, is built in a neo-Manueline style that mixes Gothic and Renaissance elements with the maritime motifs of Portugal's Age of Discovery. Inside, the rooms have intricately carved wooden ceilings and fireplaces, and they host exhibitions about the estate and its history.

Next to the palace, the small Catholic chapel is richly decorated with mosaics, frescoes and stained glass. Beneath it lies a crypt, connected, like so much here, to the underground passages.

Things not to miss

• ✓
  Walk down the Initiation Well and follow the tunnels out to the lake.
• ✓
  Cross the stepping stones beneath the Lake of the Waterfall.
• ✓
  Find the Portal of the Guardians and the Unfinished Well.
• ✓
  Climb the Regaleira Tower for views.
• ✓
  See the carved ceilings of the palace and the decorated chapel.
• ✓
  Look for hidden symbols on fountains, benches and statues.

How to get there

Trains from Lisbon's Rossio station reach Sintra in about 40 minutes. From Sintra's historic centre, Quinta da Regaleira is an easy walk of around 10 to 15 minutes along the road towards Seteais and Monserrate. Some local buses and many tuk-tuks also pass by. Parking nearby is very limited, so avoid driving if you can.

Tickets and opening hours

Tickets can be bought at the entrance or online, and buying online in advance is a good idea in summer, at weekends and on public holidays, when queues can be long. Guided tours are also available. The estate is open every day except a few holidays, with longer hours in summer. Check current prices and hours before you go.

Best time to visit

Arrive at opening time, especially between spring and autumn. The Initiation Well becomes a bottleneck later in the day, with long queues to enter the staircase. Weekdays outside school holidays are calmest. The garden is lovely in any weather, and a misty day only adds to its mysterious mood.

Where to eat nearby

There is a small café on the estate, handy for a drink. For lunch, walk back into Sintra's old town, where you'll find plenty of restaurants and the historic bakeries famous for travesseiros, almond-cream puff pastries, and queijadas, small sweet cheese tarts.

Combining your visit

Regaleira fits perfectly into a day in Sintra. Many visitors start early at Pena Palace and the Moorish Castle, then come down for lunch in the old town and spend the afternoon at Regaleira. Alternatively, pair it with the Sintra National Palace in the centre, or continue along the same road to Seteais Palace and the lush gardens of Monserrate.

Frequently asked questions

Is Quinta da Regaleira worth visiting? Absolutely. For many travellers it's the highlight of Sintra, and it feels very different from the town's grand palaces.

How long should I spend there? Allow two to three hours to see the well, tunnels, palace and garden without rushing.

Are the tunnels scary? They're dark, narrow and damp in places, but short, and they are a fun adventure for most visitors, including children.

Is it accessible? The garden is steep with many steps and uneven paths, and the well and tunnels aren't accessible to wheelchairs.

Whatever you make of its symbols, Quinta da Regaleira is a place that stays with you: a millionaire's riddle in stone, still waiting for each visitor to find their own way through it.