Built for millionaire map-maker Andrew McNally in the 1880s, this Altadena mansion has remained a mystery to the public for a century. Having passed through numerous hands over the years, today it's on the market with Deasy Penner Podley for $2,900,000 (£2,199,664). Here we reveal some incredible photos of this luxurious California estate. 

Born in Ireland to Scottish parents, Andrew McNally moved to the US in 1857 when he was 19, hoping to make his fortune. And unlike many of his fellow Irish immigrants, he did just that. First settling in Chicago, he co-founded cartography publisher Rand McNally & Co with William Rand and the pair became millionaires. In his 40s, McNally visited California for the first time and fell in love with its climate and terrain. He was determined to build himself a home here and become a 'gentleman farmer'.

McNally made good on his word, and the property he eventually built was this impressive Altadena mansion, completed in 1888 by young architect Frederick Roehrig, who is famed today. Like many Victorians at the time, McNally was also intrigued by the discoveries and developments of pioneering explorers, botanists and biologists around the world. The exotic plants he imported served as a symbol of high status, and we can see the elaborate garden design in this postcard from the era.

Originally spread over 12 acres, the three-storey house was built against the stunning mountain backdrop of the San Gabriel range, snow-capped in winter. The architectural style has been described as a "simplified Queen Anne-style" – it boasts a striking round turret, but fewer ornamental details than a conventional Queen Anne-style building. McNally opted instead for no-frills wood shingles and clapboard.

During his time in California, McNally become an advocate for the local area, convincing friends and followers to join him in the warmer climes of the Golden State. But he sadly died unexpectedly of pneumonia in 1904 and the gardens and aviary fell to neglect.

Much of the grounds were eventually sold off, but happily the house was cared for. Over the years it has had several proprietors, but it owes its current excellent condition to the Dupuy family, who maintained the house for more than 50 years. They kept the original features in good condition and ensured any restoration work was true to the original designs. Inspired? Check out these unusual celebrity properties.

The striking mansion was added to the National Register of Historic Places in 2007. At nearly 7,000 square feet, its current set up includes nine bedrooms and five bathrooms, and there are still stunning views out to Catalina Island from the property.

Every element of this estate, from its doorways and bannisters to its seven fireplaces, is rich in original, 19th-century detail. The property boasts carved woodwork, beautiful stained glass windows and wood panelling with Douglas fir. Modern upgrades to the plumbing and light fittings have been tastefully added without being intrusive.

The home is wonderfully spacious too. The ground floor is made up of large public rooms with high ceilings and huge windows that fill the space with light. Rooms extend in all directions from the open foyer, while an ornate wooden staircase sweeps up to the second floor.

The foyer itself is an impressive space with box-beam ceilings in sugar pine, a local indigenous wood. Still existing on this level are some of the original stained glass windows from the 1800s (along with a few later additions), and we see the attention to detail in the intricate designs along the panels, staircase and balustrades.

A two-sided, double fireplace is a unique feature of the ground floor. It separates the living room from a snug area that acts as a family-room-cum-library, and is a clever architectural ploy to maintain the flow of the house and remove the need for dividing walls. Delicate floral stencilling adds interest to the ceiling in both rooms.

The octagonal Turkish Room is the biggest surprise within the property's walls. With opulent Moorish touches, the room is characterised by Middle Eastern wood paneling and luxurious silken fabrics with embroidered patterns, plus bold carpets and low sofas. Arabic phrases, potentially thought to be words from the Koran, are stenciled into the upper walls. The remarkable room is 24 feet in diameter and the canopied ceiling is 24-feet high too.

There are several theories around how this room ended up in the property. A version of this room was displayed as part of the 1893 World Columbian Exhibition, which showcased global culture and design, and McNally was reportedly enamoured by the room. Some say McNally took the room apart and reassembled it in his own house – others say he commissioned a faithful copy of the space.

The front parlour would have been the main living room for the original family, and is half built into the front turret, making it a room rich in architectural interest. You can notice brilliant Victorian details too – the tiles and the mahogany of the original hearth, for example, and the ribbon detailing on the ceiling.

Sadly, the plaster in the parlour had been damaged by water and earthquakes over the years. But the new owners fixed the plaster and then repainted it with a design as close to the original as possible. A coved ceiling increases the feeling of space in the room, while generous floor-to-ceiling windows allow easy access to the porch for stunning views of the valley. Want more homes with a view? Discover these spectacular properties with mountain vistas.

Similar coved ceilings appear in the sitting room, or green room, giving the property a sense of continuity. It also has one of the most ornate of the home's seven fireplaces, with green-blue tiling and unique carvings. The green carpet extends from this room into the hallway and through to the next room, effectively joining up the space.

The dining room was and still is a grand space with no attention to detail spared. The woodwork is beautiful, in Douglas and sugar fir, with original door surrounds still existing, as well as the original built-in cabinetry. A particularly fine detail is the hand-printed frieze that wraps all the way around the room. The only new item in the room is the fireplace, which was replaced after an earthquake.

The study, or den, is much as McNally would have experienced it. You'll find an original built-in bookcase, bench and even a fireplace with attractive wooden detailing. Hiding inside the hearth there's the original coal basket, revealing that this was a coal (not a wood) fireplace. This interesting little historic fact is backed up by the fireplace's narrow structure.

Upstairs, the master bedroom is built right into the turret – this is evident from the structure of the room, with its curved walls and the inlay opposite the bed (see next photograph). Coved ceilings have again been used to make the space feel bigger, while the floral wallpaper adds to the Victorian vibe.

The unusual dimensions of the room allow for fascinating architectural workarounds, such as the placement of the white-washed fireplace in a little nook here. The fitted bench by the fireside is also from the 19th century and we can still see how the room was heated with both a fireplace and original, historic radiators.

The twin room, with its teal carpet, sumptuous peach drapes and wooden beds, emulates the period style throughout the rest of the house. Again, the fireplace is the room's standout feature, decorated in red-brown tiles that contrast with the paisley wall paper. Love historic homes? We reveal America's most endangered historic houses.

The master bathroom on the first floor is one of the most stylish and relaxing rooms in the house, complete with a stunning period-style copper bath and a bold, gilded mirror. Additional modern upgrades, such as the mirrored door and hanging plant, have been integrated into the bathroom's traditional design.

Aside from the rotund turret, the striking wraparound porch is the showpiece of the McNally Estate's façade. Architect Roehrig was committed to capitalising on the views of the San Gabriel valley and this porch is an idyllic place to sit and soak them in. It was also built high off the ground, reportedly to allow for the circulation of warm air in the hot Californian summers.

The porch hugs the front turret and can be accessed direct from the living room or the lavish foyer. Today the space is dotted with modern wicker furniture, topped with slouchy cream cushions. Guttering lines the edge of the porch so any California rain is never an issue.

The top turret room is one of the most fascinating spaces across the entire property, and was apparently used as something of a gentleman's playroom. For many years there was reportedly a billiards table here, and it was a place to escape from the bustle of the rest of the house. It's an incredible observation space, with uninterrupted views of the bucolic valley.

The up-to-date kitchen is the only room in the property that is not original. However, it is adjacent to two wonderful original butler's pantries, whose high ceilings and glass-fronted cabinets offer a glorious glimpse of the past. The new owners might want to employ a butler to make the most of them...

Over the last century, much of the original grounds and gardens have been lost in private sales, including the once-spectacular aviary. But some of the original boundary is still visible on a walk around the area, and it's possible to discern where carriages would have arrived at the original gates. We can only imagine the grand impression visitors would have had upon arriving at this turreted masterpiece. Ready for more? Discover these 'historic homes' that aren't quite what they seem.